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48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Ethernet für MAN/WAN
(Next Generation Ethernet)
48. DFN-Betriebstagung (Berlin, 27.02.2008)
Göran Friedl [email protected] Network Consultant, Nortel GmbH
3 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
(Ethernet) Next Gen Wish List
Ethernet as used today is lowest cost but has several challenges:• Service scalability • Customer segregation• Traffic engineering• Spanning Tree challenges:• stranded bandwidth• Poor convergence
• MAC explosions• Security
Cost per Mbps / CAPEX OPEXScalability Service FlexibilityNetwork Resiliency Customer SegregationSecurityEase of OAM CoS/QoSTraffic EngineeringResource Reservation
4 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Introducing Provider Backbone Bridges (PBB)
• IEEE 802.1ah (aka Mac-in-Mac) is a standard• Driven by Nortel and Cisco, supported by other
vendors
• Enables millions of service instances
• Improves security; ease of operations
802.1ahProvider BackboneBridges
802.1ad Interfaces
Provider Bridge Network (802.1ad)
Provider Backbone Bridge Network (802.1ah)
Provider Bridge Network (802.1ad)
802.1ah Interfaces
DASA
Payload
S-VIDC-VID
B-DAB-SAB-VIDI-SID
5 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Provider Backbone Bridging Operation
SW1
SW2
SW4
1/12/1
1/1 2/1MAC A SW
3MAC B
1/1
2/1
1/12/1
Bridge TableVID MAC Port205 Z 1/1205 W 2/1
Bridge TableVID MAC Port205 Z 1/1205 W 2/1
MAC C
2/2MAC Z
MAC W
Virtual Bridge SID - 100VID MAC Port.....
Virtual Bridge SID - 100VID MAC Port.....
Virtual Bridge SID - 100VID MAC Port50 A 1/150 B B-MAC W50 C B-MAC W
Virtual Bridge SID - 100VID MAC Port.....
Virtual Bridge SID - 100VID MAC Port.....
Virtual Bridge SID - 100VID MAC Port50 A B-MAC Z50 B 2/150 C 2/2
PBB Bridge TableVID MAC Port205 W 2/1
PBB Bridge TableVID MAC Port205 Z 1/1
A | C | 50
DATA
DA|SA|VID
DA|SA|VID
I-SID
- UNI
Customer MAC Learning Only at Edge NodesProvider Network Bridge Tables are small and stable
6 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
PBB: Solving Current Ethernet Challenges
Ethernet Challenges
• Service Scalability
• Customer Segregation
• Traffic engineering
• Spanning Tree challenges: • Stranded bandwidth • Poor convergence
• MAC explosions
• Security
Overlapping customer V-LANs supported
Up to 16 million service instances using 24 bit
service ID
Customer MACs learned only at the edge
Core switches only learn UNI (Backbone MAC) addresses
Customer BPDUs transparently switched
7 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Introducing Provider Backbone Transport
• P2P traffic-engineered tunnels based on existing Ethernet forwarding principles
• Simple Layer 2 networking technology• Tunnels can be engineered for diversity, resiliency or load spreading• 50 ms recovery with fast 802.1ag CFM OAM
Ethernet Metro
Traffic engineered PBT trunks
E-LINE, E-LAN
E-LINE, E-LAN
8 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
•PBT paths are protected by fast switching to an alternative pre-provisioned path.
•Only services explicitly impacted by the failure are affected
•Resilience in mesh networks is handled by Spanning Tree Protocol – many clients are affected as STP re-converges.
•Simple aggregation networks can be protected by multi-link trunking or RPR between switches.
•Forwarding tables are populated by management tool.
•Packets are never broadcast
•MAC forwarding tables are used to forward packets on a per hop basis.
•When destination is unknown, packets are broadcast and learning algorithm populates forwarding tables
Forw
ardi
ngR
esili
ence
Conventional Broadcast Ethernet PBT-enabled Ethernet
Ethernet Technology Comparison Table
9 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
PBT Value
PBT Provides… …At Ethernet Costs•Reuse existing (deployed) Ethernet technology
•Eliminate flooding and spanning tree
•Fraction of the cost of MPLS enabled switches (CAPEX)
•No learning curve for your Metro operators (OPEX)
•Connection oriented features •Traffic engineering•Resiliency•QoS•Comprehensive OAM•New standards in IEEE and ITU
•Seamless interworking to an MPLS WAN
•Solutions to QinQshortcomings
•MAC explosions, Service scalability etc…
10 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
PBT: Solving Current Ethernet Challenges
Ethernet Challenges:
• Service Scalability
• Customer Segregation
• Traffic engineering
• Spanning Tree challenges: • Stranded bandwidth • Poor convergence
• MAC explosions
• Security
260 Service Scalability
Full segregation in P2P model
End to End TEWith QoS & 50 ms recovery
Disable STPNo blocked linksFast 802.1ag convergence
MAC Explosions Eliminated
Customer BPDUs transparently switched
11 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Transport and Service Architecture PBT becomes the common infrastructure
MPLS ServicesMPLS Services(RFC 2547 VPN, PWs etc.)(RFC 2547 VPN, PWs etc.)
Ethernet ServicesEthernet Services(EVPL, ELAN, ELINE, Multicast)(EVPL, ELAN, ELINE, Multicast)
> Keep existing Ethernet, MPLS…FR/ATM…ANY & ALL services> Capitalize on Ethernet as transport for significant savings
> Existing network-friendly solution!
PBTPBT
12 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Carrier Class Ethernet OAMFully Standards based
• Comprehensive OAM & OAM hierarchy (IEEE 802.1ag) • Fault detection & notification • Continuity check, loopback connectivity check, traceroute
• Service Monitoring and performance (ITU Y.1730/31)• Frame delay, delay variation, frame loss• AIS
• Resiliency and Protection switching (ITU G.8031)
• Link layer discovery (IEEE 802.1ab)
No need to involve a parallel MPLS control plane(possible misalignment/misconfiguration between control and data
plane)
13 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Ethernet OAMIEEE 802.1ag & ITU-T Y.1730/31
1. Continuity Check (CC)a) Multicast/unidirectional heartbeat b) Usage: Fault detection
2. Loopback – Connectivity Checka) Unicast bi-directional request/responseb) Usage: Fault verificationc) Not implemented in control plane
3. Traceroute (i.e., Link trace) a) Trace nodes in path to a specified target nodeb) Usage: Fault Isolationc) Traceroute is not available for MPLS PWs over MPLS tunnels
4. Alarm Indication Signal (AIS): Under discussion in Y.17ethoama) Propagate data path fault notificationsb) Usage: Alarm suppression
5. Discovery (not specifically supported by .1ag however Y.17ethoam and 802.1ab support it)a) Service (e.g. discover all PEs supporting common service instance)b) Network (e.g. discover all devices (PE and P) common to a domain)
6. Performance Monitoring (not specifically supported by .1ag however Y.17ethoam supports it)a) Frame Delayb) Frame Delay Variationc) Frame Loss Items in ORANGE are not available in MPLS OAM
EdgeSwitch
EdgeSwitch
TransitSwitch
Adapt Adapt
NNILink
NNILink
UNILink
UNILink
Link OAMTrunk OAM
Service OAM (SID)
customer demarcs
Link OAM Link OAM
14 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
• Configured MAC forwarding operation (just like PBT), this time by a shortest path Link State Routing Protocol (IS-IS)
• PLSB and existing Ethernet control protocols can operate side-by-side in the same network infrastructure
• Optimal shortest path p2mp trees for distribution of broadcast/multicast• Loop suppression without port blocking (packet-by-packet) with RPFC• Fast network convergence
root
AA->
<-A
A->
DX
TODAY with (R)STP
A
D
Shortest Paths with PLSB
XX
B
Multicast Tree from D to A, B & C
C
Provider Link State Bridging (PLSB; IEEE 802.1aq)Carrier grade ELAN without Spanning Tree
15 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
PLSB Approach
• If Ethernet is going to be there….use it!• Take advantage of Ethernet’s more capable data plane
• Virtual partitions (VLANS), scalable multicast, comprehensive OAM
• PLSB uses a Link State protocol – IS-IS• IS-IS floods topology and service info (B-MAC and I-SID
information)• Integrate service discovery into the control plane • PLSB nodes use link state information to construct unicast
and per service (or I-SID) multicast connectivity
Combines well-known networking protocol with well-known data plane to build an efficient service infrastructure
16 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Virtual broadcast domains constructed via IS-IS
PLSB Fundamentals
• > For each B-VLAN assigned to this mode of operation :• flooding is disabled & all ports are unblocked• Control plane configures shortest path unicast
and multicast connectivity between PBBs• Loop suppression is applied to B-MAC packets
• PLSB delivers a better B-MAC layer for MAC-in-MAC• MAC-in-MAC already isolates C-MACs from B-MACs in the
core and keeps C-MAC state at the edge• C-MAC flooding, multicast and broadcast maps to scoped B-
MAC multicast• C-MAC to Virtual Port (= B-MAC) bindings are learned at the
edge as in conventional bridged operation
17 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
PLSB Implementation
• PLSB discovers the network automatically setting up a shortest path distribution tree without blocking any links
• Each node creates its Shortest Path tree to all other nodes in the network
Network Topology Shortest Path tree from ES1
18 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Defining services using PLSB
• As PBB service endpoints (ISIDs) are added, all PLSB nodes will be aware of all service locations.
• Each PLSB node will know if it is on the shortest path for each ISID and install the appropriate FIB state to ensure connectivity, thereby creating per service multicast tree
Shortest Path tree from ES1 Multicast tree for all nodes supportingISID 100 (ES1, ES7, ES11)
19 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Router
Replication performed/distributed to many nodes
Only ONE copy of a packet per physical link
What Ethernet does well…packet replication for mcast/bcast
20 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Traffic following shortest pathRouter
Router
Ethernet Distributed replication model
Per VPN, customized Bcast Domain. Dynamically established (no core
provisioning)
Router
Router
No duplication of packets per physical link
fast resiliency
What Ethernet does well…now add PLSB!
21 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
The Next Stage of Ethernet Evolution
Traffic following spanning tree path Router
Router
Spanning tree Forces blocked links
Orphaning Bandwidth
• PBB has evolved the Ethernet data plane for pt-to-pt
• PLSB evolves the Ethernet control plane
• PLSB …• Eliminates blocked ports• Better traffic distribution• Greater 3 fold increase in
failure recovery (on order of 250ms)
• No catastrophic “root” failures• Shortest path forwarding• Broadcast containment within
service community
22 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
The Next Stage of Ethernet Evolution
• PBB has evolved the Ethernet data plane for pt-to-pt
• PLSB evolves the Ethernet control plane
• PLSB …• Eliminates blocked ports• Better traffic distribution• Greater 3 fold increase in
failure recovery (on order of 250ms)
• No catastrophic “root” failures• Shortest path forwarding• Broadcast containment within
service communityNo Blocked Links!!
No Orphaned Bandwidth
Traffic following shortest path
Tandem nodes can easily be service nodes too
23 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
PLSB Simplified Operation
Signal PWEsN2 manual session creation
Required for Auto-DiscoverySeparate RR topologies (to help scale)
Eases burden of statically managing VSI PWE’s
Base LDPs: build LSP tunnelsRedundant to IGP (same paths)
Base IGP: TopologyRequired for network topology knowledge
Physical LinksLink layer headers striped off, label lookup
per node
IGP (IS-IS or OSPF)
LDP or RSVP-TE
E-LDP
SONET, SDH, Ethernet, etc…
BGP-AD
Tunn
el L
SP P
roto
cols
VPN
Pro
toco
ls
PLSB (IS-IS)
Ethernet
One IGP for Topology & Discovery-One protocol now provides -auto-discovery-fast fault detection-network healing -shortest path
Physical Links: - Link layer headers reused as a label lookup through every node
Tunn
el +
VP
N P
roto
cols
Typical VPLS Implementation: PLSB Implementation:
Minimizing control plane = Minimized complexity = Reduced cost
24 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
State of the Standards
Standard Topic State
802.1ah
802.1Qay
802.1ag
802.1AB
802.1p/ad
802.1aq
Y.1731
PBB (Hierarchy in the metro) Complete
PBT (aka PBB-TE) expected completion late 2008
Connectivity Management Complete
Auto-discovery Complete
Class Based Queuing Complete
PLSB Working group since Jan 2008
Connectivity & Performance Mgmt Complete
25 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Nortel’s Metro Ethernet Networks Native Ethernet, existing network-friendly solutions
• Lowest cost (CAPEX & OPEX) Packet Optimized Metro Infrastructure
• High Density Ethernet leveraging industry silicon• Superior grooming and fill• Bandwidth efficient solutions for Access & Core
• Delivers the broadest suite of SLAs and Services in the industry
• TE capability for trunking• Advanced OAM Tools• Strong QoS
• Scales to massive service delivery • Allows for PW or Ethernet Service Adaptation• Scalable to millions of customers
• Strong, simple comprehensive OAM• Robust toolset for monitoring and debugging • Ethernet OAM integrated with Sonet-like service
Predictable, Scalable & Operational Metro Ethernet Networks
Cost per Mbps / CAPEX OPEXScalability Service FlexibilityNetwork Resiliency
Customer SegregationSecurityEase of OAM CoS/QoSTraffic EngineeringResource Reservation
27 48. DFN48. DFN--Betriebstagung Betriebstagung -- Berlin, 27.02.2008Berlin, 27.02.2008
Acronyms
DA destination address
CAPEX Capital expenses
IGP Interior Gateway Protocol
LDP Label Distribution Protocol
MPLS Multiprotocol label switching
OPEX Operational expenses
CFM Connectivity Fault Management
I-SID I-component Service ID
MAC address (media access control) address is the unique hardware address of a network node
MAC MiM Mac in Mac 802.1ah, also known as provider backbone bridging
OAM operations, admin and maintenance
OSS operations support system
PBB Provider Backbone bridging
PBT provider backbone transport; now PBB traffic engineering
PLSB Provider Link State Bridging
PW pseudowire
QoS quality of service
RPR resilient packet ring
SLA Sevice Level Agreement
SA source address
SID service ID
STP/RSTP spanning tree protocol, rapid spanning tree protocol
VLAN virtual local area network
VID VLAN ID
VPN virtual private network