Advances in BGPd2zmdbbm9feqrf.cloudfront.net/2013/usa/pdf/BRKRST-3371.pdf · Advances in BGP BRKRST-3371 Gunter Van de Velde Sr. Technical Leader [email protected] . ... (VPLS) DC

Advances in BGP BRKRST-3371

Gunter Van de Velde

Sr. Technical Leader

[email protected]

© 2013 Cisco and/or its affiliates. All rights reserved. BRKRST-3371 Cisco Public

What is BGP?

3

Without BGP the Internet would not exist in its current stable and simple form

It is the plumbing technology of the Internet

What a Google search “bgp abbreviation” finds?

– Source: http://www.all-acronyms.com/BGP

Border Gateway Protocol Bacterial Growth Potential Battlegroup Becker, Green and Pearson <sensored entry>

Bermuda grass pollen Berri Gas Plant beta-glycerophosphate biliary glycoprotein blood group bone gamma-carboxyglutamic acid protei… bone gamma-carboxyglutamic acid-contai… bone gla protein bone Gla-containing protein Borders Group, Inc. brain-type glycogen phosphorylase Bridge Gateway Protocol Broader Gateway Protocol Bureau de Gestion de Projet Brain Gain Program

http://www.all-acronyms.com/BGP/Border_Gateway_Protocol/4870

http://www.all-acronyms.com/BGP/Bacterial_Growth_Potential/851409

http://www.all-acronyms.com/BGP/Battlegroup/1129015

http://www.all-acronyms.com/BGP/Becker,_Green_and_Pearson/1003328

http://www.all-acronyms.com/BGP/Bermuda_grass_pollen/849470

http://www.all-acronyms.com/BGP/Berri_Gas_Plant/1223429

http://www.all-acronyms.com/BGP/beta-glycerophosphate/848267

http://www.all-acronyms.com/BGP/biliary_glycoprotein/846387

http://www.all-acronyms.com/BGP/blood_group/55208

http://www.all-acronyms.com/BGP/bone_gamma-carboxyglutamic_acid_protein/850178

http://www.all-acronyms.com/BGP/bone_gamma-carboxyglutamic_acid-containing_protein/847202

http://www.all-acronyms.com/BGP/bone_gla_protein/55209

http://www.all-acronyms.com/BGP/bone_Gla-containing_protein/850193

http://www.all-acronyms.com/BGP/Borders_Group,_Inc./42974

http://www.all-acronyms.com/BGP/brain-type_glycogen_phosphorylase/849876

http://www.all-acronyms.com/BGP/Bridge_Gateway_Protocol/1279817

http://www.all-acronyms.com/BGP/Broader_Gateway_Protocol/96403

http://www.all-acronyms.com/BGP/Bureau_de_Gestion_de_Projet/197282

http://www.all-acronyms.com/BGP/Brain_Gain_Program/1319634


What is BGP? – What it truly is?

4

The Bloody Good Protocol


Agenda

Motivation to Enhance BGP

Scale and Performance Enhancements

What happened in BGP Landscape?

Some new Cool features that may interest you

5


Agenda





6


BGP started in 1989…

Motivation and Development of BGP: When the Internet grew and moved to an autonomous system (AS) mesh architecture it was needed to have stable, non-chatty and low CPU consuming protocol to connect all of these AS’s together.

In June 1989, the first version of this new routing protocol was formalized, with the publishing of RFC 1105, A Border Gateway Protocol (BGP).

7


Service Provider Routing and Services progress

Multimedia, Mobile Internet and Cloud Services will generate massive bandwidth explosion

Prefix growth is almost a linear curve

Evolution of offered BGP services go from basic technologies to very advanced infrastructures

8


Control-plane Evolution Most of services are progressing towards BGP

9

Service/transport 2008x and before 2013 and future

IDR (Peering) BGP BGP (IPv6)

SP L3VPN BGP BGP + FRR + Scalability

SP Multicast VPN PIM BGP Multicast VPN

DDOS mitigation CLI BGP flowspec

Network Monitoring SNMP BGP monitoring protocol

Security Filters BGP Sec (RPKI), DDoS Mitigation

Proximity BGP connected app API

SP-L3VPN-DC BGP Inter-AS, VPN4DC

Business & CE L2VPN LDP BGP PW Sign (VPLS)

DC Interconnect L2VPN BGP MAC Sign (EVPN)

MPLS transport LDP BGP+Label (Unified MPLS)

Data Center OSPF/ISIS BGP + Multipath

Massive Scale DMVPN NHRP / EIGRP BGP + Path Diversity

Campus/Ent L3VPN BGP (IOS) BGP (NX-OS)


Why BGP is so successful ?

Robustness: Run over TCP

Low Overhead protocol: sends an update once and then remains silent

Scalability: Path Vector Protocol, allows full mesh

High Availability: NSR, PIC,…

Well Known : Tons of engineers know BGP

Simplicity: BGP is simple (even if knobs make BGP BIG and sometimes less trivial to read)

Multi-protocol: IPv4, IPv6, L2VPN, L3VPN, Multicast

Incremental: easy to extend: NLRI,Path Attribute, Community

Flexible: Policy

10


Agenda





11


Scale & Performance Enhancements

Update Generation Enhancements – Update generation is the most important, time-critical task

– Is now a separate process, to provide more CPU Quantum

Parallel Route Refresh – Significant delay (up to 15-30 minutes) seen in advertising incremental updates while RR is servicing route refresh requests or

converging newly established peers

– Refresh and incremental updates run in parallel

Keepalive Enhancements – Loosing or delayed keep-alive message result in session flaps

– Hence keep-alive processing is now placed into a separate process using priority queuing mechanism

Adaptive Update Cache Size – Instead of using a fixed cache size, the new code dynamically adapts to the address family used, the available router memory

and the number of peers in an update group

BGP Scaling

12


Scale & Performance Enhancements

PE Scaling

–PE-CE Optimization In old code slow convergence was experienced with large numbers of CE’s

Improved by intelligently evaluating VPN prefixes based upon the prefixes in the CE’s VRF

–VRF-Based Advertise Bits Increased memory consumption when number of VRF’s was scaled on a PE

Smart reuse of advertise bit space for VRF

Route Reflector Scaling

–Selective RIB Download A Route-Reflector needs to receive the full RIB, however not all prefixes MUST be in the Forwarding Information Base (FIB)

So, we now allow by using user policy to only download selected prefixes in the FIB

More about BGP Performance tuning in BRKRST-3321

13


BGP Resiliency/HA Enhancement

Issue: Slow peers in update groups block convergence of other

update group members by filling message queues/transmitting slowly

Persistent network issue affecting all BGP routers

Two components to solution

Detection

Protection

Detection

BGP update timestamps

Peer’s TCP connection characteristics

Slow Peer Management

14



Protection

Move slower peers out of update group

Separate slow update group with matching policies created

Any slow members are moved to slow update group

Detection can be automatic or manual with CLI command

Automatic recovery

Slow peers are periodically checked for recovery

Recovered peers rejoin the main update group

Isolation of slow peers unblocks faster peers and lets them converge as fast as possible


15



Static protection

[no] neighbor … slow-peer split-update-group static

Dynamic detection [no] bgp slow-peer detection [threshold <seconds>]

Dynamic protection

[no] neighbor … slow-peer detection [threshold <seconds>]

[no] bgp slow-peer split-update-group dynamic [permanent]

[no] neighbor … slow-peer split-update-group dynamic [permanent]


16

for your reference


ASR1000 RP2, RP1, ASR1001 and 7200 BGP Route and Session Scalability Comparison - RR

• Tested with BGP selective download feature for ipv4/ipv6 for dedicated RR application. This feature prevents ipv4/ipv6 BGP routes to be installed in RIB and FIB. It reduces memory usage per ipv4/ipv6 prefix and CPU utilization

• ASR 1000 with RP1 allocates ~1.7GB to IOSd, ASR 1001 with 4GB allocates ~1.4GB to IOSd, whereas on NPE-G2 entire 2G is used by IOS

7200 NPE-

G2 (2GB)

ASR1000

RP1 (4GB)

ASR1001

(4GB)

ASR1001

(8GB)

ASR1001

(16GB)

ASR1000

RP2 (8GB)

ASR1000

RP2 (16GB)

ipv4 routes 4M 7M* 2M* 9M* 17M* 12M* 29M*

vpnv4 routes 7M 6M 2M 8M 16M 10M 24M

ipv6 routes 2M 5M* 2M* 8M* 15M* 9M* 24M*

vpnv6 routes 6M 5M 1.5M 7.5M 14.5M 9M 21M

BGP

sessions <1000 4000 4000 4000 4000 8000 8000

for your reference

17


ASR 1000 RP1 and RP2 Convergence Performance Comparison - RR

Tested with peer groups (1K RR clients per peer group)

7200 NPE-G2 can not converge in the above test cases.

ASR1000 RP2 converges about twice faster than 7200 NPE-G2 based on RR customer profile testing

CPU utilization below 5% after convergence

Link to Isocore report http://www.cisco.com/en/US/prod/collateral/routers/ps9343/ITD13029-ASR1000-RP2Validationv1_1.pdf

Tested with 1M Total Unique

Routes

Total Routes Reflected by RR

to All Clients (Number of

routes x Number of Clients)

ASR1000 RP1 (4GB)

Convergence

(in seconds)

ASR1001 (16GB)

Convergence

(in seconds)

ASR1000 RP2 (16GB)

Convergence

(in seconds)

ipv4 (1K RR clients) 1Billion 220 133 75

vpnv4 (1K RR clients, 8K RT) 1Billion 680 489 221

ipv6 (1K RR clients) 1Billion 720 393 194

vpnv6 (1K RR clients, 8K RT) 1Billion 877 811 293

ipv4 (2K RR clients) 2 Billion 375 270 138

vpnv4 (2K RR clients, 8K RT) 2 Billion 1285 797 394

ipv6 (2K RR clients) 2 Billion 1126 897 284

vpnv6 (2K RR clients, 8K RT) 2 Billion 1766 1691 551

for your reference

18

http://www.cisco.com/en/US/prod/collateral/routers/ps9343/ITD13029-ASR1000-RP2Validationv1_1.pdf











Agenda





19


What Happened in XR Landscape?

20

4.0 4.1 4.1.1 4.2 4.2.1 4.2.3 4.2.4 4.3.0 4.3.1

• Add Path Support

• Accumulated

Interior Gateway

Protocol (AIGP)

Metric Attribute

• Unipath PIC for

non-VPN address-

families

(6PE/IPv6/IPv4

Unicast)

• RT-Constraint

• BGP Accept Own

• Multi-Instance/Multi-AS

• BGP 3107 PIC Update

for Global Prefixes

• Prefix Origin Validation

based on RPKI

• PIC for RIB and FIB

• Attribute Filtering and

Error handling

• DMZ Link Bandwidth for

Unequal Cost Recursive

Load Balancing

• Selective VRF Download

• 6PE/6vPE over L2TPv3

• Next-Generation

Multicast VPN

• BGP Based DDoS

Mitigation


What Happened in IOS Landscape?

21

15.2(1)S 15.2(2)S 15.2(4)S 15.3(1)S 15.3(2)S

Origin AS Validation

Gracefull Shutdown

iBGP NSR

mVPN BGP SAFI 129

NSR without Route-Refresh

Additional Path

Attribute Filtering and Error Handling

Diverse Path

Graceful Shutdown

IPv6 client for Single hop BFD

IPv6 PIC Core and Edge

RT Constraint

IP Prefix export from a VRF into global Table

mVPNv6 Extranet Support

Local-AS allow-policy

RT/VPN-ID Attribute Rewrite Wildcard

VRF Aware Conditional Announcement


What Happened in XE Landscape?

22

3.8 3.9

Multicast VPN BGP Dampening

Multiple Cluster IDs

VPN Distinguisher Attribute

IPv6 NSR

Local-AS Allow-policy

RT or VPN-ID Rewrite Wildcard

VRF Aware Conditional Advertisement


What Happened NXOS Landscape?

23

5.2 6.0 6.1 6.2

Default information originate support

Flexible distance manipulation with

Inject map

Unsupress map

as-format command for AS-plain & AS-dot

Enhancements for removal of private AS

enable route target import-export in default VRF

InterAS option B-lite

BGP Authentication for Prefix-based neighbors

BGP AddPath

BGP send community both

BGP Neighbor AF weight command

BGP med confed and AS multipath-relax

BGP next hop self for route reflector

Prefix Independent Convergence (Core)

local-as

AS Override (allowas-in)

Disable 4-byte AS advertisement

MP BGP – MPLS VPNs, 6PE, MDT


Agenda





24

The Bloody Good Protocol


PIC Edge Feature Overview

25

Internet Service Providers provide strict SLAs to their Financial and Business VPN customers where they need to offer a sub-second convergence in the case of Core/Edge Link or node failures in their network

Prefix Independent Convergence (PIC) has been supported in IOS-XR/IOS for a while for CORE link failures as well as edge node failures

BGP Best-External project provides support for advertisement of Best-External path to the iBGP/RR peers when a locally selected bestpath is from an internal peer

BGP PIC Unipath provides a capability to install a backup path into the forwarding table to provide prefix independent convergence in case of the PE-CE link failure


10.1.1.0/24 VPN1 Site #1

MPLS Cloud

Traffic Flow 10.2.2.0/24 VPN1 Site

#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR

PIC Edge: PE-CE Link Protection

PE3 configured as primary, PE4 as backup –PE3 preferred over PE4 by local preference

–CE2 has different RDs in VRFs on PE3 and PE4

–PE4: advertise-best-external, to advertise route via PE4-CE2 link

–PE3: additional-paths install, to install primary and backup path


26


10.1.1.0/24 VPN1 Site #1

MPLS Cloud


#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR

PIC Edge: Link Protection

PE3 has primary and backup path

– Primary via directly connected PE3-CE2 link

– Backup via PE4 best external route

What happens when PE3-CE2 link fails?


27


10.1.1.0/24 VPN1 Site #1

MPLS Cloud


#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR


CEF (via BFD or link layer mechanism) detects PE3-CE2 link failure

– CEF immediately swaps to repair path label Traffic shunted to PE4 and across PE4-CE2 link


28


10.1.1.0/24 VPN1 Site #1

MPLS Cloud

Traffic Flow

10.2.2.0/24 VPN1 Site

#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR

Withdraw route via PE3


PE3 withdraws route via PE3-CE2 link

– Update propagated to remote PE routers


29


10.1.1.0/24 VPN1 Site #1

MPLS Cloud

Traffic Flow

10.2.2.0/24 VPN1 Site

#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR

Withdraw route via PE3


BGP on remote PEs selects new bestpath

– New bestpath is via PE4

– Traffic flows directly to PE4 instead of via PE3


30


10.1.1.0/24 VPN1 Site #1

MPLS Cloud


#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR

PIC Edge: Edge Node Protection

PE3 configured as primary, PE4 as backup

– PE3 preferred over PE4 by local preference

– CE2 has different RDs in VRFs on PE3 and PE4

– PE4: advertise-best-external, to advertise route via PE4-CE2 link

– PE1: additional-paths install, to install primary and backup path


31


10.1.1.0/24 VPN1 Site #1

MPLS Cloud

Traffic Flow

10.2.2.0/24 VPN1 Site

#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR


PE1 has primary and backup path

– Primary via PE3

– Backup via PE4 best external route

What happens when node PE3 fails?


32


10.1.1.0/24 VPN1 Site #1

MPLS Cloud

Traffic Flow

10.2.2.0/24 VPN1 Site

#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR

PE3’s /32 host route

removed from IGP




33


10.1.1.0/24 VPN1 Site #1

MPLS Cloud

Traffic Flow

10.2.2.0/24 VPN1 Site

#2

PE1

PE2

PE3

PE4

CE1 CE2

Primary

Backup

RR

PE3’s /32 host route

removed from IGP


PE1 detects loss of PE3’s /32 host route in IGP

– CEF immediately swaps forwarding destination label from PE3 to PE4 using backup path

BGP on PE1 computes a new bestpath later, choosing PE4


34


Enabling BGP PIC – Enabling IP Routing Fast Convergence

BGP PIC leverages IGP convergence Make sure IGP converges quickly

IOS-XR: IGP Timers pretty-much tuned by default

IOS: Sample OSPF config:

35

process-max-time 50

ip routing protocol purge interface

interface …

carrier-delay msec 0

negotiation auto

ip ospf network point-to-point

bfd interval 100 min_rx 100 mul 3

router ospf 1

ispf

timers throttle spf 50 100 5000

timers throttle lsa all 0 20 1000

timers lsa arrival 20

timers pacing flood 15

passive-interface Loopback 0

bfd all-interfaces

for your reference


Enabling BGP PIC Edge: IOS-XR

Two BGP-PIC Edge Flavors: BGP PIC Edge Multipath and Unipath

Multipath: Re-routing router load-balances across multiple next-hops, backup next-hops are actively taking traffic, are active in the routing/forwarding plane, commonly found in active/active redundancy scenarios.

– No configuration, apart from enabling BGP multipath (maximum-paths ... )

Unipath: Backup path(s) are NOT taking traffic, as found in active/standby scenarios

36

route-policy backup ! Currently, only a single backup path is supported

set path-selection backup 1 install [multipath-protect] [advertise]

end-policy

router bgp ...

address-family ipv4 unicast

additional-paths selection route-policy backup

!

address-family vpnv4 unicast

additional-paths selection route-policy backup

!

for your reference


Enabling BGP PIC Edge: IOS

As in IOS-XR, PIC-Edge w/ multipath requires no additional configuration

PIC-Edge unipath needs to be enabled explicitly ...

37

router bgp ...

address-family ipv4 [vrf ...]

or

address-family vpnv4

bgp additional-paths install

http://www.cisco.com/en/US/docs/ios/iproute_bgp/configuration/guide/irg_bgp_mp_pic.html

http://www.cisco.com/en/US/docs/ios/ios_xe/iproute_bgp/configuration/guide/irg_best_external_xe.html

... or implicitly when enabling best external

router bgp ...

address-family ipv4 [vrf ...]

or

address-family vpnv4

bgp advertise-best-external

for your reference


Question: How will my PE’s learn about the alternate Paths?

By default my RR Only-Reflects the Best-Route

38

RR

PE2

PE3

Z NH:PE3, P:Z

NH:PE2, P:Z

PE1

Prefix Z

Via PE2

E0

E0

Prefix Z

Via E0

Prefix Z

Via E0

NH:PE2, P:Z


Diverse BGP Path Distribution Shadow Session

Easy deployment – no upgrade of any existing router is required, just new iBGP session per each extra path (CLI knob in RR1)

Diverse iBGP session does announce the 2nd best path

39

RR1

NH:PE2, P:Z

NH:PE2, P:Z

Prefix Z

Via PE2

Via PE3 NH:PE3, P:Z

NH:PE3, P:Z

PE2

PE3

Z

PE1


BGP Add-Path

Add-Path will signal diverse paths from 2 to X paths

Required all Add-Path receiver BGP router to support Add-Path capability.

40

RR1 NH:PE2, P:Z AP 1 NH:PE2, P:Z

Prefix Z

Via PE2

Via PE3 NH:PE3, P:Z AP 2

NH:PE3, P:Z

PE2

PE3

Z PE1


BGP Add-path flavors

IETF defines 5 flavors of Add-x-Path. 2 are implemented by Cisco:

Add-n-path: with add-n-path the route reflector will do best path computation for all paths and send n best to BR/PE.

– Usecase: Primary + n-1 Backup scenario. (n is maximal for IOS-XR 2 and 3 for IOS).

Add-all-path: with add-all-path, the route reflector will do the primary best path computation (only on first path) and then send all path to BR/PE.

– Usecase: Large DC ECMP load balancing, hot potato routing scenario

Cisco innovation: Add-all-multipath and Add-all-multipath+backup in XR 4.3.1

41

for your reference


Add-Path Applications

Fast convergence / connectivity restoration – As the ingress routers have visibility to more paths, they can switch to the backup paths faster once the primary path goes away. Requires backup paths to be sent.

Load balancing – As the ingress routers have visibility to more paths, they can do ECMP on multiple paths. Requires either backup paths or all paths to be sent.

Churn reduction – since alternate paths are available, withdraws can be suppressed (implicit update).

Route oscillation – see RFC 3345 for scenarios. Requires group best paths (in some cases all paths) to be sent.

42


Add-Path Configuration – IOS-XR

Enable in global address-family mode

– Enables for all IBGP neighbors

Enable/Disable in neighbor mode

43

router bgp 100


additional-paths send

!


additional-paths send

!

neighbor 1.1.1.1

remote-as 100


!


!

!

neighbor 2.2.2.2

remote-as 100

capability additional-paths send disable


!

for your reference



Enable in global address-family mode

– Enables for all IBGP neighbors

Enable/Disable in neighbor mode

44

router bgp 100


additional-paths receive

!


additional-paths receive

!

neighbor 1.1.1.1

remote-as 100


!


!

!

neighbor 2.2.2.2

remote-as 100

capability additional-paths receive

disable


!

!

!

for your reference



Path selection is configured in a route-policy

Configuration in VPNv4 mode applies to all VRF IPv4-Unicast AF modes unless overridden at individual VRFs

45

route-policy ap1

if community matches-any (1:1) then

set path-selection backup 1 install

elseif destination in (150.0.0.0/16, 151.0.0.0/16) then

set path-selection backup 1 advertise install

endif

end-policy

!

route-policy ap2

set path-selection all advertise

end-policy

!

route-policy ap3

set path-selection backup 1 install

end-policy

!

for your reference



Add-Path Path Selection

46

router bgp 100


additional-paths selection route-policy ap1

!



!

vrf foo

rd 1:1



!

!

vrf bar

rd 2:2


!

for your reference


PIC Edge: Test Results

Test Setup Node Failure Link Failure

No PIC Edge, No BFD 12-14 sec 8-17 sec

BFD Only 10-12 sec 6-12 sec

PIC Edge Only 8 sec 4 sec

PIC Edge, BFD 0 sec 0 sec


47

for your reference


Automated Route Target Filtering

Increased VPN service deployment increases load on VPN routers

–10% YOY VPN table growth

–Highly desirable to filter unwanted VPN routes

Multiple filtering approaches

–New RT filter address family

–Extended community ORF

BGP Feature

48



Derive RT filtering information from VPN RT import lists automatically

Exchange filtering info via RT filter AF or extended community ORF

Translate filter info received from neighbors into outbound filtering policies

Generate incremental updates for received RT update queries

Incremental deployment possible/desirable

49

BGP Feature


PE-1

PE-2

PE-3

PE-4

RR-1 RR-2

VRF- Blue

VRF- Red

VRF- Red

VRF- Green

RT-Constraint:

NLRI= {VRF-Blue, VRF-Red}

RT-Constraint:

NLRI= {VRF-Green, VRF-Purple}

RT-Constraint:

NLRI= {VRF-Purple, VRF-Blue}

RT-Constraint:

NLRI= {VRF-Red, VRF-Green}

RT-Constraint:

NLRI= {VRF-Blue, VRF-Red, VRF-Green}

RT-Constraint:

NLRI={VRF-Green, VRF-Purple, VRF-Blue}

VRF- Green

VRF- Purple

VRF- Purple

VRF- Blue


50

Improves PE and RR scaling and performance by sending only relevant VPN routes

router bgp as-number

address-family rtfilter unicast

neighbor {ip-address | peer-group-name} activate

neighbor {ip-address | peer-group-name} send-community extended

end


Accept own

51

This feature allows movement from a PE-Based service provisioning model to a centralized router reflector (RR)-based service provisioning model. With this feature, you can define route TO service-VRF mapping within a centralized route reflector and then propagate this information down to all the PE clients of that RR. Without this feature, you would define the route TO service VRF mapping in all PE devices, thereby incurring a high configuration overhead, which could result in more errors.

This feature enables a route reflector to modify the Route Target (RT) list of a VPN route that is distributed by the route reflector, enabling the route reflector to control how a route originated within one VRF is imported into other VRFs.

router#configure

router(config)#router bgp 100

router(config-bgp)#neighbor 10.2.3.4

router(config-bgp-nbr)#address-family vpnv4 unicast

router(config-bgp-nbr-af)#accept-own


AIGP (Accumulated IGP Metric Attribute for BGP)

http://tools.ietf.org/html/draft-ietf-idr-aigp-09

Optional, non-transitive BGP path attribute

BGP attribute to provide BGP a way to make its routing decision based on the IGP metric, to choose the “shortest” path between two nodes across different AS.

The main driving force for this feature is to solve the IGP scale issue seen in some ISP core network.

Mainly to be deployed to carry nexthop prefixes/labels across different AS within the same administrative domain.

The remote ingress PE select its best path using the modified best path selection process using AIGP metric.

Overview – AIGP

52


Overview – AIGP

Sending/Receiving AIGP attribute • Per-session configuration

• Enabled for iBGP session by default

• Disabled for eBGP session by default, a knob to enable the AIGP capability

• AIGP attribute received on an AIGP-disabled sessions should be treated as an unrecognized non-transitive attribute.

Origination of AIGP metric • By configuration

• Redistribution IGP or static

• BGP network

• Inbound/outbound policy

for your reference

53


Overview – AIGP

Modification of AIGP attribute • By Originator

• A new BGP update should be issued

• Configurable threshold to minimize IGP instability – not in 4.0

• By non-originator

• When NH is not changed – no change for the AIGP attribute value

• When NH is changed to non-recursive IGP or static route – increase the AIGP attribute value by the NH distance

• When NH is changed to recursive BGP-learned or static route – increase the AIGP attribute value by recursively resolving and increasing the AIGP attribute value of the NHs until either the NH is non-recursive or the NH is a BGP route without AIGP attribute

• AIGP value change triggers new AIGP computation for the route

• AIGP carried across different AS with different IGP domain may not offer a meaningful result.

for your reference

54


Overview – AIGP

Modified best path calculation • Modifications in the tie breaking procedures

• Changes made after local_preference comparison

• When a route has AIGP attribute

① Remove from considering routes without AIGP attribute

» - this can be overruled by configuring a knob

① Compare routes of the cumulative AIGP value

• When the NH has AIGP attribute

① Compute the “interior cost” as the cumulative AIGP value for the NH

② Compare routes using the modified IGP cost

Update generation • Different update groups for neighbors of AIGP-capable, non-AIGP capable or

neighbors enabled to send AIGP value in cost-community.

• BGP update is generated upon AIGP value change

for your reference

55


Overview – AIGP

Passing AIGP attribute to non-AIGP capable neighbors • Translate AIGP into cost-community

• 2 POI of pre-best-path and igp-cost are supported

• A transitive keyword to make cost-comm transitive to eBGP neighbors

• Redistribute BGP (with AIGP) into IGP –

• Translate AIGP value into BGP MED

Other software components • Route installation – for BGP to tag AIGP metric during route installation

• NH notification – when AIGP metric changed

– Update generation throttling is not supported in XR4.0

– It is highly recommended to deploy BGP best-external and Additional-path in conjunction with the AIGP attribute, to effectively achieve the desired routing policy.

56


AIGP: Originating AIGP

router bgp 1


redistribute ospf 1 route-policy set_aigp_1

route-policy set_aigp_1

if destination in (61.1.1.0/24 le 32) then

set aigp-metric 111

elseif destination in (2100::1:0/112,

2100::2:0/112) then

set aigp-metric igp-cost

Endif

end-policy

AIGP is enabled between iBGP neighbors by default

AIGP between eBGP neighbors need to be enabled

AIGP can be originated by using redistribute ospf, redistribute isis, redistribute

static or the BGP network command.

AIGP can also be originated using neighbor address-family inbound or

outbound policy to set AIGP to be the IGP cost or to a fixed value.

for your reference

57


AIGP capability verification #1:

RP/0/0/CPU0:router-RR#show bgp neighbor 110.33.33.3 BGP neighbor is 110.33.33.3 Remote AS 1, local AS 1, internal link Remote router ID 110.30.30.3 Cluster ID 110.50.50.5 BGP state = Established, up for 3w4d NSR State: NSR Ready Last read 00:00:24, Last read before reset 00:00:00 Hold time is 180, keepalive interval is 60 seconds Configured hold time: 180, keepalive: 60, min acceptable hold time: 3 Last write 00:00:55, attempted 19, written 19 Second last write 00:01:55, attempted 19, written 19 Last write before reset 00:00:00, attempted 0, written 0 Second last write before reset 00:00:00, attempted 0, written 0 Last write pulse rcvd Aug 6 11:48:49.296 last full Jul 12 12:05:24.042 pulse count 72908 Last write pulse rcvd before reset 00:00:00 Socket not armed for io, armed for read, armed for write Last write thread event before reset 00:00:00, second last 00:00:00 Last KA expiry before reset 00:00:00, second last 00:00:00 Last KA error before reset 00:00:00, KA not sent 00:00:00 Last KA start before reset 00:00:00, second last 00:00:00 Precedence: internet Non-stop routing is enabled Graceful restart is enabled Restart time is 120 seconds Stale path timeout time is 360 seconds

For Address Family: IPv4 Unicast BGP neighbor version 34101 Update group: 0.3 Route-Reflector Client AF-dependent capabilities: Graceful Restart capability advertised and received Neighbor preserved the forwarding state during latest restart Local restart time is 120, RIB purge time is 600 seconds Maximum stalepath time is 360 seconds Remote Restart time is 120 seconds Additional-paths Send: advertised Additional-paths Receive: advertised and received Route refresh request: received 0, sent 0 0 accepted prefixes, 0 are bestpaths Cumulative no. of prefixes denied: 0. Prefix advertised 31470, suppressed 0, withdrawn 3525 Maximum prefixes allowed 524288 Threshold for warning message 75%, restart interval 0 min AIGP is enabled An EoR was received during read-only mode Last ack version 34101, Last synced ack version 34101 Outstanding version objects: current 0, max 4 Additional-paths operation: Send

Neighbor capabilities: Route refresh: advertised and received Graceful Restart (GR Awareness): received 4-byte AS: advertised and received Address family IPv4 Unicast: advertised and received Address family IPv4 Labeled-unicast: advertised and received Address family VPNv4 Unicast: advertised and received Address family IPv6 Labeled-unicast: advertised and received Address family VPNv6 Unicast: advertised and received Received 36025 messages, 0 notifications, 0 in queue Sent 42771 messages, 0 notifications, 0 in queue Minimum time between advertisement runs is 0 secs

for your reference

58


RP/0/1/CPU0:olympic-12c-lr1#sh bgp 61.1.1.0/24 bestpath-compare BGP routing table entry for 61.1.1.0/24

Versions:

Process bRIB/RIB SendTblVer

Speaker 31709 31709

Last Modified: Aug 6 06:05:44.392 for 00:26:12

Paths: (2 available, best #1)

Not advertised to any peer

Path #1: Received by speaker 0


Local

110.11.11.1 (metric 2) from 110.55.55.5 (110.10.10.1)

Origin incomplete, metric 3, localpref 100, aigp metric 111, valid, internal, best, group-best

Received Path ID 1, Local Path ID 1, version 31709

Originator: 110.10.10.1, Cluster list: 110.50.50.5

best of local AS, Overall best

Path #2: Received by speaker 0


Local

110.22.22.2 (metric 2) from 110.55.55.5 (110.20.20.2)

Origin incomplete, metric 3, localpref 100, aigp metric 211, valid, internal, backup, add-path

Received Path ID 3, Local Path ID 3, version 31709

Originator: 110.20.20.2, Cluster list: 110.50.50.5

Higher AIGP metric than best path (path #1)

AIGP metric verification #2: receive route with AIGP metric from RR best-path calculation considered AIGP metric

RP/0/1/CPU0:olympic-12c-lr1#sh route 61.1.1.0/24

Routing entry for 61.1.1.0/24

Known via "bgp 1", distance 200, metric 113 (AIGP metric)

Number of pic paths 1 , type internal

Installed Aug 6 06:05:44.152 for 00:33:50

Routing Descriptor Blocks

110.11.11.1, from 110.55.55.5

Route metric is 113

110.22.22.2, from 110.55.55.5, BGP backup path

Route metric is 113

No advertising protos.

for your reference

59


What is Multi-Instance BGP?

60

A new IOS-XR BGP architecture to support multiple instances along the lines of OSPF instances

Each BGP instance is a separate process running on the same or a different RP/DRP node

The BGP instances do not share any prefix table between them

No need for a common adj-rib-in (bRIB) as is the case with distributed BGP

The BGP instances do not communicate with each other and do not set up peering with each other

Each individual instance can set up peering with another router independently


What is Multi-AS BGP?

61

It will be possible to configure each instance of a multi-instances BGP with a different AS number

Global address families can’t be configured under more than one AS except vpnv4 and vpnv6

VPN address-families may be configured under multiple AS instances that do not share any VRFs


Why Multi-Instance/Multi-AS?

It provides a mechanism to consolidate the services provided by multiple routers using a common routing infrastructure into a single IOS-XR router

It provides a mechanism to achieve AF isolation by configuring the different AFs in different BGP instances

It provides a means to achieve higher session scale by distributing the overall peering sessions between multiple instances

It provides a mechanism to achieve higher prefix scale (especially on a RR) by having different instances carrying different BGP tables

IOS-XR CRS Multi-chassis systems can be used optimally by placing the different BGP instances on different RP/DRPs

It is the base of Cisco’s SP DDoS Mechanism

62


Configuration Example for your reference

63


Show Command Example RP/0/0/CPU0:ios#sh bgp instances

Number of BGP instances: 4

ID Placed-Grp Name AS VRFs Address Families

--------------------------------------------------------------------------------

0 v4_routing ipv4 1 0 IPv4 Unicast

1 bgp2_1 ipv6 1 0 IPv6 Unicast

2 bgp3_1 vpn1 3 1 VPNv4 Unicast

3 bgp4_1 vpn2 3 1 VPNv4 Unicast

RP/0/0/CPU0:ios#sh bgp instance ?

WORD Specify the bgp instance name

all Choose all BGP instances

RP/0/0/CPU0:ios#sh bgp instance all ?

A.B.C.D IPv4 network

A.B.C.D/length IPv4 network and masklength

advertised Show advertised routes

af-group Show config information on address family groups

all Both ipv4 and ipv6 address families

attribute-key Display networks with their associated attribute key index

cidr-only Display only routes with non-natural netmasks

community Display routes matching the communities

convergence Test an address family for convergence

…

for your reference

64


Show Command Example

RP/0/0/CPU0:ios#sh bgp instance all sessions

Wed Sep 28 20:45:56.917 PDT

BGP instance 0: 'ipv4'

======================

Neighbor VRF Spk AS InQ OutQ NBRState NSRState

10.0.101.1 default 0 1 0 0 Established -

BGP instance 1: 'ipv6'

======================



BGP instance 2: 'vpn1'

======================



BGP instance 3: 'vpn2'

======================



for your reference

65


Attribute Filtering and error-handling

Attribute filtering

– Unwanted optional transitive attribute such as ATTR_SET, CONFED segment in AS4_PATH causing outage in some equipments.

– Prevent unwanted/unknown BGP attributes from hitting legacy equipment Block specific attributes

Block a range of non-mandatory attributes

Error-handling

– draft-ietf-idr-optional-transitive-04.txt

– Punishment should not exceed the crime

– Gracefully fix or ignore non-severe errors

– Avoid session resets for most cases

– Never discard update error, as that can lead to inconsistencies

66


Architecture

67

Invalid

Attribute Contents

Wrong Attribute

Length Unknown Attributes Unwanted Attributes

Malformed BGP Updates Transitive Attributes

Attribute Filtering

Error-handling

NLRI processing…


Attribute filtering

First level of inbound filtering

Filtering is configured as a range of attribute codes and a corresponding action to take (Note: Never Discard Update as that can lead towards inconsistencies)

Actions

– Discard the attribute

– Treat-as-withdraw

Applied when parsing each attribute in the received Update message

– When a attribute matches the filter, further processing of the attribute is stopped and the corresponding action is taken

68

for your reference


Error-handling

Comes into play after attribute-filtering is applied

When we detect one or more malformed attributes or NLRIs or other fields in the Update message

Steps

– Classification of errors

– Actions to be taken

– Logging

69

for your reference


Error-handling details

Classification of errors

– Minor: invalid flags, zero length, duplicates, optional-transitive attributes

– Medium: Non-optional-transitive attributes, inconsistent attribute length

– Major: Invalid or 0 length nexthop

– Critical: NLRI parsing, inconsistent message / total attributes length

Actions taken

– Local repair

– Discard attribute

– Treat-as-withdraw

– Reset session

– Discard Update message

70

for your reference


Support client functionality of RPKI RTR protocol

Separate database to store record entries from the cache

Support to announce path validation state to IBGP neighbors using a well known path validation state extended community

Modified route policies to incorporate path validation states

BGP Origin Validation

71


Prefix hijacking

Announce someone else’s prefix

Announce a more specific of someone else’s prefix

Either way, you are trying to “steal” someone else’s traffic by getting it routed to you

– Capture, sniff, redirect, manipulate traffic as you wish

72

Source: nanog 46 preso


How does the Solution look like?

73


Configuration sample

router bgp 64726

bgp always-compare-med

bgp log-neighbor-changes

bgp deterministic-med

no bgp default ipv4-unicast

bgp rpki server tcp 217.193.137.117 port 30000 refresh 60

bgp rpki server tcp 2001:918:FFF9:0:250:56FF:FE15:159 port 8282 refresh 60

bgp rpki server tcp 2001:918:FFF9:0:250:56FF:FE15:159 port 30000 refresh 60

bgp rpki server tcp 217.193.137.117 port 8282 refresh 600

neighbor 2001:428:7000:A:0:1:0:1 remote-as 64209

neighbor 2001:428:7000:A:0:1:0:1 description "To Qwest MPLS"

74

for your reference


Valid vs Unknown vs Invalid routes?

JSV-ASR#sho bgp sum

BGP router identifier 66.77.8.142, local AS number 64726

BGP table version is 11688639, main routing table version 11688639

Path RPKI states: 38286 valid, 1574331 not found, 4558 invalid

404300 network entries using 59836400 bytes of memory

1617175 path entries using 103499200 bytes of memory

66778/66761 BGP path/bestpath attribute entries using 9081808 bytes of memory

62642 BGP AS-PATH entries using 2273670 bytes of memory

1347 BGP community entries using 70456 bytes of memory

0 BGP route-map cache entries using 0 bytes of memory

0 BGP filter-list cache entries using 0 bytes of memory

BGP using 174761534 total bytes of memory

808583 received paths for inbound soft reconfiguration

BGP activity 744131/330548 prefixes, 7084275/5448612 paths, scan interval 60 secs

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd

63.231.216.9 4 64726 17784 17789 11688639 0 0 1d01h 3

65.119.97.101 4 64209 0 0 1 0 0 16:57:38 Idle (Admin)

66.77.8.129 4 209 216390 4021 11688634 0 0 2d12h 404293

66.77.8.130 4 209 212278 4020 11688634 0 0 2d12h 404290

66.77.8.150 4 64726 70180 227968 11688639 0 0 1d16h 3

JSV-ASR#

75

for your reference


What do you see in the BGP table?

JSV-ASR#sho bgp

BGP table version is 11698585, local router ID is 66.77.8.142

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

Network Next Hop Metric LocPrf Weight Path

V*> 0.0.0.0/1 0.0.0.0 0 32768 i

V* i 66.77.8.150 0 100 100 i

N* 0.0.0.0 66.77.8.130 0 1000 209 i

N*> 66.77.8.129 0 1000 209 i

N* 1.0.0.0/24 66.77.8.130 7800038 1000 209 15169 i

N*> 66.77.8.129 7800038 1000 209 15169 i

N* 1.0.4.0/22 66.77.8.130 8000039 1000 209 4323 7545 7545 7545 7545 56203

i

N*> 66.77.8.129 8000039 1000 209 4323 7545 7545 7545 7545 56203

i

N* 1.0.16.0/23 66.77.8.130 8000039 1000 209 2914 2519 i

N*> 66.77.8.129 8000039 1000 209 2914 2519 i

N* 1.0.18.0/23 66.77.8.130 8000039 1000 209 2914 2519 i

N*> 66.77.8.129 8000039 1000 209 2914 2519 i

N* 1.0.20.0/23 66.77.8.130 8000039 1000 209 2914 2519 i

76

for your reference


Multicast VPN Solution Space

(complete solution is now available)

77

LSM Encapsulation

/Forwarding IP/GRE

P2MP TE (pt-mpt)

PIM (pt-mpt)

Core Tree

Signaling MLDP

(pt-mpt | mpt-mpt)

mVPN

IPv4

Native

IPv6

mVPN

IPv6

Service Native

IPv4

BGP PIM C-Multicast

Signaling

PORT


BGP customer-multicast signaling and BGP

auto-discover is now added to the multicast

VPN solution.

Multicast VPN – BGP Signaling

BGP as overlay allows Service Providers to

capitalize on a single protocol

Auto-Discovery of PEs and

Core tree/tunnel information

PE1

PE2

PE3

PE4

CE1 CE3

RR

Receiver Source

CE4 Receiver CE2

RP

BGP Auto-Discovery

BGP C-mroutes

PIM C-Join

(*,G) or (S,G)

PIM C-Join

(*,G) or (S,G)

Advertisement of Customer

Multicast routes

BGP

78


BGP Graceful Shutdown

RFC 6198 – April 2011

Old Behaviour

– If session drops then BGP will withdraw all prefixes learned over that session

– BGP has no mechanism to signal prefix will soon be unreachable (for maintenance for example)

Historically RR’s have worsened the issue as they tend to hide the alternate path as they only forward the best path

79

BGP Graceful Shutdown allows to do maintenance on router without service disruption.

This new knob allows a router to notify neighbor to redirect traffic to other paths and after some time will drop BGP sessions.

The notification could be done using Local Preference attribute

or user community attribute

#Graceful Shutdown

Please wait…

BGP/ Prefix 10.45 / localpref : 10

1 2

Traffic is

redirected

3


Graceful Shutdown

GSHUT well-known community

The GSHUT community attribute is applied to a neighbor specified by the neighbor shutdown graceful command, thereby gracefully shutting down the link in an expected number of seconds

The GSHUT community is specified in a community list, which is referenced by a route map and then used to make policy routing decisions.

80

http://www.cisco.com/en/US/docs/ios-xml/ios/iproute_bgp/configuration/15-s/irg-15-s-book.pdf

neighbor {ipv4-address | ipv6-address | peer-group-name} shutdown graceful seconds {community

value [local-preference value] | local-preference value}





















DDoS Mitigation – a stepstone approach

Phase III

– Dynamic application aware redirection and traffic handling

Phase II

– Malicious traffic mitigation

– Cleaning of Malicious traffic

– Dirty and clean traffic handling

– Usage of Multi-instance BGP

Phase I

– ACL

– RTBH

– PBR

– uRPF

IOS-XR 4.3.1

IOS-XE partial

81


DDoS Overview

Distributed denial-of-service (DDoS) attacks target network infrastructures or computer services by sending overwhelming number of service requests to the server from many sources.

Server resources are used up in serving the fake requests resulting in denial or degradation of legitimate service requests to be served

Addressing DDoS attacks

Detection – Detect incoming fake requests

Mitigation Diversion – Send traffic to a specialized device that removes the fake packets from the traffic stream while retaining the legitimate packets

Return – Send back the clean traffic to the server

82


DDOS impact on Customer Business

83


DDOS impact on customer Business

Enterprise customer can’t defend themselve, when DDoS hit the FW… it’s already too late.

SP could protect enterprise by cleaning DDoS traffic at ingress peering point.

New revenue for SP.

Mandated service to propose to Financial and visible customers.

for your reference

84


DDoS trends (Nanog source)

Any Internet Operator Can Be a Target for DDoS

Ideologically-motivated ‘Hacktivism’ and On-line vandalism DDoS attacks are the most commonly identified attack motivations

Size and Scope of Attacks Continue to Grow at an Alarming Pace

High-bandwidth DDoS attacks are the ‘new normal’ as over 40% of respondents report attacks greater than 1 Gbps and 13% report attacks greater than 10Gbps

Increased sophistication and complexity of layer-7 DDoS attacks, multi-vector DDoS attacks becoming more common

First-Ever Reports of IPv6 DDoS Attacks 'in the Wild' on Production Networks

for your reference

85


DDoS mitigation architecture 1. Detection (no DDoS)

DDOS

scrubber

Security

Server

DDOS

Analyser

Sample

Netflow

Scan Netflow data

to detect DDOS attacks

86


DDoS mitigation architecture 2. Detection (DDOS)

DDOS

scrubber

Security

Server

DDOS

Analyser

Sample

Netflow

Scan Netflow data

Find DDOS signature

87


DDoS mitigation architecture 3. Redirect traffic to DDOS scruber

DDoS

scrubber

Security

Server

DDoS

Analyser

Scan Netflow data

Find DDoS signature

BGP DDoS Mitigation

Action: redirect to DDoS

scrubber

88


DDoS Mitigation: Architecture Considerations

Normal traffic flow when there is no attack

Redirect traffic from any edge PE to any specific DDoS scrubber

Including the PE that is connected to the host network

Granular (prefix level/network) diversion

Customers buy DDoS mitigation service for some prefixes

Pre-provisioned DDoS service for those prefixes (using policy such as standard community flag)

Centralized controller that injects the diversion route

VPN based Labeled return path for the clean traffic

To prevent routing loops

Solution support redirection of BGP less/more specific prefixes or local originated prefixes (static route, redistributed route)

Support for multi-homed customers

During attack, send clean traffic from DDOS scrubber to multiple PE’s

89


The concept

90

Traffic under normal conditions

Internet users

Traffic under normalized

conditions • Traffic takes shortest path

• Upstream and downstream traffic follow

traditional routing

Server

Scrubber

ISP

Pre-provisioned DDoS

instrumentation • Traffic Scrubber

Separate clean and malicious traffic

• Security Analyser

Analyses Netflow/IPFIX statistics from the

traffic flows

• Security server

Actions upon traffic analysis by

communication to infrastructure routers

Security analyser

Security server

PE3

PE2

PE1


BGP based DDoS

91

Traffic under DDoS condition

Internet users

Traffic under DDoS condition • Traffic is redirected to a scrubber

• Scrubber separates the clean from

the malicious traffic

• Clean traffic is returned to original

destination server

Goal • Do not drop all traffic

• Collect traffic intelligence

• Operational simplicity

• Easy to remove redirect when traffic

normalizes

Server Scrubber

ISP

Security analyser

Security server

PE3

PE2

PE1


How does it work?

92

Normal traffic condition

Internet users

• All PE’s peer with the RR

• All PE’s exchange both Global

Internet and VPN prefixes

• All PE interfaces are non-VPN

• Security analyser is performing

doing analyses

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

Security analyser

Security server

Destination Next-hop

1.1.1.1/32 2.2.2.2

PE3

PE2

PE1


How does it work?

93

Server is under DDoS

Internet users

• Flow is detected as dirty by

Security analyser

• Result: Server is under attack

• Traffic needs to be redirected to the

scrubber to mitigate the attack

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

Security analyser

Security server


1.1.1.1/32 2.2.2.2

PE3

PE2

PE1


How does it work?

94

Internet users

• DDoS Route-Reflector was pre-

visioned

• Mitigation route to 1.1.1.1/32 is

injected on the DDoS RR by the

Security server


pointing to 3.3.3.3 on DDoS

mitigation RR

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

Security server

DDoS

Route-Reflector

6.6.6.6


1.1.1.1/32 3.3.3.3

PE3

PE2

PE1



How does it work?

95

Internet users


pointing to 3.3.3.3 is signalled to all

PE’s

• All PE’s receive the mitigation route

from the DDoS Mitigation RR

• Each PE will now have 2 routes to

reach 1.1.1.1/32

• Which route will the PE use?

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

Security server

DDoS

Route-Reflector

6.6.6.6


1.1.1.1/32 3.3.3.3


1.1.1.1/32 2.2.2.2

1.1.1.1/32 3.3.3.3


1.1.1.1/32 ????????????

BGP Table Routing Table

PE3

PE2

PE1



How does it work?

96

Internet users

Trick # 1 • The DDoS mitigation route will

ALWAYS be preferred, even if

• Both prefix lengths are the

same

• DDoS prefix is shorter

• Original prefix has better

administrative distance

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

Security server

DDoS

Route-Reflector

6.6.6.6


1.1.1.1/32 2.2.2.2

1.1.1.1/32 3.3.3.3


1.1.1.1/32 3.3.3.3

Routing Table BGP Table

PE3

PE2

PE1



How does it work?

97

Internet users

• The mitigated traffic flows towards

PE3 (3.3.3.3)

• PE3 is sending the dirty flow

towards the scrubber

• The scrubber will

• Handle and remove the dirty

traffic within the original flow

• Send the cleaned traffic

towards the original destination

(1.1.1.1 at PE2 (2.2.2.2))

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

DDoS

Route-Reflector

6.6.6.6


1.1.1.1/32 2.2.2.2

1.1.1.1/32 3.3.3.3


1.1.1.1/32 3.3.3.3


PE3

PE2

Clean

traffic

PE1



How does it work?

98

Internet users

Problem • Scrubber sends traffic to PE3

• PE3 does routing lookup for 1.1.1.1

and finds that it is directly attached

• ROUTING LOOP!!!

• How do we fix this?

• We use a new isolated routing

table for the clean traffic

• This routing table is Pre-

provisioned Inside a VPN

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

DDoS

Route-Reflector

6.6.6.6


1.1.1.1/32 2.2.2.2

1.1.1.1/32 3.3.3.3


1.1.1.1/32 3.3.3.3


PE3

PE2

Clean

traffic

PE1



How does it work?

99

Internet users

Server Scrubber

ISP

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4


1.1.1.1/32 2.2.2.2

1.1.1.1/32 3.3.3.3

Destination Next-hop VPN

1.1.1.1/32 3.3.3.3 Global

1.1.1.1/32 2.2.2.2 Clean


PE3

PE2

• The clean traffic will be injected upon PE3

on an interface member of VPN Clean

• PE3 will now do a routing destination

lookup for 1.1.1.1 in VPN Clean

• The matching routing table entry is

pointing towards PE2 at 2.2.2.2

• The clean flow, which is now part of VPN

Clean is sent towards PE2 reachable at

2.2.2.2

VPN Clean

PE1



How does it work?

100

Internet users

Server Scrubber

ISP

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

PE3

PE2 CE1


1.1.1.1/32 3.3.3.3 Global

1.1.1.1/32 CE1 Clean

Routing Table • PE2 receives the clean flow

within VPN clean

• PE2 does a destination address

routing lookup in VPN clean

• A matching route is found in VPN

clean

• Flow is forwarded towards CE1

onwards to Server

HOLD on a minute! PE2 does not have any interface part of VPN clean

All interfaces on PE2 are global interfaces

so how did that clean route for 1.1.1.1 get into VPN

clean?

PE1



How does it work?

101

Internet users

Server Scrubber

ISP

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

Destination Next-

hop

VPN

1.1.1.1/32 CE1 Global

1.1.1.1/32 3.3.3.3 Global

1.1.1.1 CE1 clean

BGP Table

PE3

PE2 CE1

Trick # 2 • Copy the locally BGP inserted route

directly into VPN clean BGP table

• Neighbour details are inherited from

the global table (i.e.)

• Outgoing interface

• Next-hop

• Interface pointing towards CE1 is

NOT VPN aware

• This VPN clean distributed as normal

VPN

• New CLI command to do that import from default-vrf route-policy ddos

advertise-as-vpn


1.1.1.1/32 3.3.3.3 Global

1.1.1.1/32 CE1 Clean

Routing Table

PE1


Going back to traditional traffic flow

102

Internet users

• Remove the routing entry on the

Mitigation DDoS RR

• No more route is remaining on

the DDoS Mitigation RR

• Traffic flows normally again

Server Scrubber

ISP

Internet and VPN

Route-Reflector

1.1.1.1/32

2.2.2.2

3.3.3.3

4.4.4.4

5.5.5.5

Security server

DDoS

Route-Reflector

5.5.5.5


1.1.1.1/32 3.3.3.3

PE1



Configuration (1)

router bgp 99 instance ddos

bgp router-id 3.3.3.3

bgp read-only

bgp install diversion


!

router bgp 99

bgp router-id 2.2.2.2


!

Creation of DDoS BGP

instance

Allows config of 2th IPv4 or IPv6 instance

Suppresses BGP Update Generation

Triggers BGP ddos instance to install

diversion path to RIB, so that the paths

are pushed down to FIB

for your reference

103


Configuration (2)

vrf clean


import from default-vrf route-policy ddos advertise-as-vpn

export route-target

111:1

!

!


import from default-vrf route-policy ddos advertise-as-vpn

export route-target

111:1

!

!

!

Importing the global route’s in the clean VRF

104


“show” commands

RP/0/0/CPU0:hydra-prp-A#show route Codes: C - connected, S - static, R - RIP, B - BGP, (>) - Diversion path D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, su - IS-IS summary null, * - candidate default U - per-user static route, o - ODR, L - local, G - DAGR A - access/subscriber, a - Application route, (!) - FRR Backup path Gateway of last resort is not set O 1.0.11.0/24 [110/2] via 13.0.3.1, 00:36:19, GigabitEthernet0/2/1/5 O 1.1.1.1/32 [110/2] via 13.0.3.1, 00:36:19, GigabitEthernet0/2/1/5 L 2.2.2.2/32 is directly connected, 00:37:24, Loopback0 O 3.3.3.3/32 [110/2] via 87.0.1.2, 00:36:19, GigabitEthernet0/2/1/9 O 4.4.4.4/32 [110/3] via 13.0.3.1, 00:36:19, GigabitEthernet0/2/1/5 [110/3] via 87.0.1.2, 00:36:19, GigabitEthernet0/2/1/9 B 5.5.5.5/32 [200/0] via 1.1.1.1, 00:34:22 B > [200/0] via 123.0.0.2, 00:34:22 [...]

for your reference

105


“show” commands (1)

RP/0/0/CPU0:hydra-prp-A#show route Codes: C - connected, S - static, R - RIP, B - BGP, (>) - Diversion path D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, su - IS-IS summary null, * - candidate default U - per-user static route, o - ODR, L - local, G - DAGR A - access/subscriber, a - Application route, (!) - FRR Backup path Gateway of last resort is not set O 1.0.11.0/24 [110/2] via 13.0.3.1, 00:36:19, GigabitEthernet0/2/1/5 O 1.1.1.1/32 [110/2] via 13.0.3.1, 00:36:19, GigabitEthernet0/2/1/5 L 2.2.2.2/32 is directly connected, 00:37:24, Loopback0 O 3.3.3.3/32 [110/2] via 87.0.1.2, 00:36:19, GigabitEthernet0/2/1/9 O 4.4.4.4/32 [110/3] via 13.0.3.1, 00:36:19, GigabitEthernet0/2/1/5 [110/3] via 87.0.1.2, 00:36:19, GigabitEthernet0/2/1/9 B 5.5.5.5/32 [200/0] via 1.1.1.1, 00:34:22 B > [200/0] via 123.0.0.2, 00:34:22 [...]

for your reference

106


“show” commands (2) RP/0/0/CPU0:hydra-prp-A#show route 5.5.5.5/32


Known via "bgp 2394-ro", distance 200, metric 0, type internal

Installed Feb 19 22:56:45.896 for 00:34:33


1.1.1.1, from 1.1.1.1

Route metric is 0

123.0.0.2, from 101.0.0.4, Diversion Path (bgp)

Route metric is 0


RP/0/0/CPU0:hydra-prp-A#show cef 5.5.5.5/32 det

5.5.5.5/32, version 60652, internal 0x14000001 (ptr 0xaf6e3840) [1], 0x0 (0x0), 0x0 (0x0)

Updated Feb 19 22:56:46.723

local adjacency 87.0.1.2

Prefix Len 32, traffic index 0, precedence n/a, priority 4

gateway array (0xae07a310) reference count 2, flags 0x8020, source rib (5), 0 backups

[1 type 3 flags 0xd0141 (0xae10f8c0) ext 0x420 (0xaec261e0)]

LW-LDI[type=0, refc=0, ptr=0x0, sh-ldi=0x0]

via 123.0.0.2, 2 dependencies, recursive [flags 0x6000]

path-idx 0 [0xaf6e3c00 0x0]

next hop 123.0.0.2 via 123.0.0.0/24

Load distribution: 0 (refcount 1)

Hash OK Interface Address

0 Y GigabitEthernet0/2/1/9 87.0.1.2

for your reference

107


“show” commands (3)

RP/0/0/CPU0:hydra-prp-A# show route 123.0.0.2


Known via "ospf 100", distance 110, metric 2, type intra area



87.0.1.2, from 3.3.3.3, via GigabitEthernet0/2/1/9

Route metric is 2


RP/0/0/CPU0:hydra-prp-A#

RP/0/0/CPU0:hydra-prp-A#show route 1.1.1.1


Known via "ospf 100", distance 110, metric 2, type intra area



13.0.3.1, from 1.1.1.1, via GigabitEthernet0/2/1/5

Route metric is 2


for your reference

108


Summary

109

Bloody Good Protocol





110


Maximize your Cisco Live experience with your

free Cisco Live 365 account. Download session

PDFs, view sessions on-demand and participate in

live activities throughout the year. Click the Enter

Cisco Live 365 button in your Cisco Live portal to

log in.

Complete Your Online Session Evaluation

Give us your feedback and you could win fabulous prizes. Winners announced daily.

Receive 20 Cisco Daily Challenge points for each session evaluation you complete.

Complete your session evaluation online now through either the mobile app or internet kiosk stations.

111

Documents

Advances in BGPd2zmdbbm9feqrf.cloudfront.net/2013/usa/pdf/BRKRST-3371.pdf · Advances in BGP BRKRST-3371 Gunter Van de Velde Sr. Technical Leader [email protected] . ... (VPLS) DC