Catalyst 3750 & 3560 Architectured2zmdbbm9feqrf.cloudfront.net/2011/las/pdf/BRKARC-3437.pdf · One ―Universal‖ IOS image contains all IOS features Licensing enables a specific

Catalyst 3750 & 3560Architecture

Albert Mitchell

Technical Marketing

BRKARC-3437

© 2011 Cisco and/or its affiliates. All rights reserved. Cisco PublicBRKARC-3437 22

The Differences between Catalysts 3K models

What is a stack?

Do I have 1 or 2 rings in my stack?

Is my stack redundant?

What is Flexstack, is it better than Stackwise?

What is StackPower?

Stackwise = 9 switches but Stackpower = 4 switches

How do I build my stack?

Can I mix any Catalyst 3k in one stack?

Can I mix any IOS feature set in one stack?

How does QoS work?

Questions We Will Answer Today


Agenda

Switch Differences

Hardware Overview

StackWise and Flexstack

StackPower

Stack Functions & Operations

QoS Model

Summary

Packet Walks


Stackable switches

Catalyst 3750v2, 3750G, 3750E, and 3750-X

Standalone switches

Catalyst 3560v2, 3560G, 3560-E, and 3560-X

Aggregation Models

Catalyst 3560E-12SD, 3560-12D, 3750X-12SD,

and 3750X-24SD

Compact Catalyst 2960C and 3560C

Catalyst 3K Product Family


Cisco StackPower

Stackwise Plus / FlexStack

Uplink Network modules

Hardware Encryption

Full PoE and PoE+ support – 30W per port

Redundant Field replaceable power supplies

Redundant Field replaceable Fan modules

LAN Base model

USB support for storage and console

Universal Software Image:

LAN Base, IPBase, and IPServices

Aggregation

Compact or reduced density of ports!

Catalyst 3K Main featuresDifferentiators

3750-E

3560-E

3750G

X-Series


Catalyst 3750-X Series

Stackable Next Gen Gigabit Ethernet 24 and 48 port

Data and PoE+ Models

Innovative features, StackPower, PoE+,

Encryption, Dual redundant PS, Network modules

Three IOS feature sets:

LAN Base

IP Base

IP Services

Enhanced LLW:

Next business day (NBD) advance hardware

replacement

90 Day access to Cisco Technical Assistance

Center (TAC) support

Full Energy-Wise support

Catalyst 3560-X Series

Standalone

Catalyst 3750-X and 3560-X SeriesSuperset


There Are Three Images Available for the Classic Non E-Series Switches:

1. IP-Base (L2,Stub routing, IP ACLs)

2. IP Services (Full L3 Routing and Multicast routing)

IOS Images and Feature setsV2 and G series

3 Distinct Images

3. Advanced IP services (IPv6 Routing)

IPv6 Routing

PACL, RACL, VACL

2 Distinct Images


One ―Universal‖ IOS image contains all IOS features

Licensing enables a specific level of IOS functionality

Easy upgrades, only install a license to upgrade functionality

Capability to create its own demo license – valid for 60 days

New LAN Base feature set

One Universal Image for X-Series

Universal IOS

Image

IPv6

Routing


LAN Base: Comprehensive Layer 2 switching for Catalyst 2960, 2960S, 3560X, 3750X, and Compact switches

Only the Catalyst X-Series switches are upgradeable

IP Base: Entry level Layer 3 switching for Catalyst 3560 and 3750 E and X Series, and Compact switches.

Minimum feature set to enable Stackpower and Encryption

IP Services: Advanced Layer 3 switching for Catalyst 3560 and 3750 E and X Series

IOS Feature Set Capabilities Catalyst 2k & 3k

White Paper on Licenses for C3750E, C3750Xhttp://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/white_paper_c11-579326_ps10745_Products_White_Paper.html

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/white_paper_c11-579326_ps10745_Products_White_Paper.html




Show commands to administer software licensing:

Displaying the file

Detailed display of license type

Showing the Unique Device Identifier

Enabling debug mode

Show Commands

show license file [switch <switch_id>]

show license status [switch <switch_id>]

show license detail <feature_name> [switch

<switch_id>]

show license udi

debug license <events | all | errors>


License Store: Primary License Storage

StoreIndex: 0 Feature: ipbase Version: 1.0

License Type: Permanent

License State: Active, Not in Use

License Priority: Medium

License Count: Non-Counted

License Store: Evaluation License Storage

StoreIndex: 0 Feature: ipservices Version: 1.0

License Type: Evaluation

License State: Active, In Use

Evaluation total period: 8 weeks 4 days

Evaluation period left: 8 weeks 3 days

Expiry date: Apr 30 1993 00:00:09

License Priority: Low

License Count: Non-Counted

Show Commands

Switch# Show license all


Types of Software LicensesPermanent & Temporary licenses

The permanent license is node-locked because it is bound to the unique device identifier (UDI)

A temporary license is limited to a usage period and can be one of these types:

• Embedded evaluation license in the software image

The evaluation license is node-locked and is valid for 60 days.

• Extension license

Get this license from Cisco TAC; It is node-locked and is valid for 60 days.

• Grace-period license

During rehost process, when the license on a switch is revoked and transferred to another switch, this license is automatically installed to prevent network disruption – valid for 60 days

After the usage period expires, the switch continues to use the

temporary software license until it is restarted.


Minimum IOS 12.2(46)SE

Create Your Own Evaluation License!

Switch# license boot level ipservices

Supported license levels are:

ipservices

ipbase

PLEASE READ THE FOLLOWING TERMS CAREFULLY. INSTALLING THE LICENSE OR

LICENSE KEY PROVIDED FOR ANY CISCO PRODUCT FEATURE OR USING SUCH

PRODUCT FEATURE CONSTITUTES YOUR FULL ACCEPTANCE OF THE FOLLOWING

TERMS. YOU MUST NOT PROCEED FURTHER IF YOU ARE NOT WILLING TO BE BOUND

BY ALL THE TERMS SET FORTH HEREIN.

You hereby acknowledge and agree that the product feature license is terminable and that the product feature enabled by such license may be shut

down or terminated by Cisco after expiration of the applicable term of the license (e.g., 30-day trial period). Cisco reserves the right to terminate or shut

down any such product feature electronically or by any other means available. While alerts or such messages may be provided, it is your sole responsibility

to monitor your terminable usage of any product feature enabled by the license and to ensure that your systems and networks are prepared for the shut down

of the product feature. You acknowledge and agree that Cisco will not have any liability whatsoever for any damages, including, but not limited to, direct,

indirect, special, or consequential damages related to any product feature being shutdown or terminated. By clicking the "accept" button or typing "yes" you are

indicating you have read and agree to be bound by all the terms provided herein.

ACCEPT? (yes/[no]):

*Apr 2 02:04:08.604: %IOS_LICENSE_IMAGE_APPLICATION-6-LICENSE_LEVEL:

Module name = c3750e Next reboot level = advipservices and License = advipservices


QoS Model

Switch Differences

Hardware Overview


StackPower


Summary

Packet Walks

Agenda


Architecture OverviewProcessor

Switch-to-Switch communication and synchronization

Updates the MAC and Routing caches attached to each port ASIC

Performs CPU Software-based forwarding when the TCAM is over its limits for MACs, Routes, ACL entries etc.

The CPU communicates with the Port ASICs via a dedicated management ring (the yellow ring in the diagram)

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

StackWise,

StackWise

Plus

24X1G POE 24X1G POE

Two Stack

Cables

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY


Architecture OverviewSwitch Fabric

128Gbps switching Fabric

Provides line rate and local switching within a switch and stack connectivity

48G + 2X10G + 32 Stack-ports (100Gbps FDX)

64 Gbps Ring Stackwise Plus

1 Gbps Ring Inter-connect control path to the Port ASICs to the CPU

Point-to-Point, 32 Gbps ring connecting each Port ASIC

Jumbo frame switching and routing

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

StackWise,

StackWise

Plus

24X1G POE 24X1G POE

Two Stack

Cables

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 PortPHY

8 PortPHY


SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

StackWise,

StackWise

Plus

24X1G POE 24X1G POE

Two Stack

Cables

8 PortPHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY

Architecture OverviewPort ASIC

The Port ASIC performs:

Pre-pend a 24-byte header for internal use

Traffic forwarding

QoS

ACL lookup

The number of Port ASICs varies, depending on media speed and type of ports.

I.e., Gig ports, SFP ports, 10Gig ports


Architecture OverviewTCAM/SRAM

The TCAM stores vital information including IPv4, IPv6 and MAC addresses

The 3750-X TCAM/SRAM is incorporated into the Port ASIC

Hardware Merge process to pack entries into TCAM

SRAM tables have been sized to fit all existing Catalyst 3750 SDM templates

With the 3750-E it is now easier to pack the full 2K ACEs into TCAM

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

StackWise,

StackWise

Plus

24X1G POE 24X1G POE

Two Stack

Cables

TCAM

SRAM

TCAM

SRAM

TCAM

SRAM

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY


Architecture OverviewPHY – includes Link Encryption

MACsec link encryption in hardware – Line rate

All media conversion

10/100/1000 MbpsFX, LX/LH, SX, ZX, BX (1490 & 1310Nm), CWDM, DWDM

10G, Supported:

LR (SMF 10km), LRM, SR (MMF), CX1, CX3, CX5

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

StackWise,

StackWise

Plus

24X1G POE 24X1G POE

Two Stack

Cables

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY


Ring View of the Switch Fabric

Physically, the ring is a series of switch fabrics strung together by stack cables

The switch fabric performs token generation and ring control

Stack PHYSwitch Fabric

Stack PHYSwitch Fabric

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

StackWise,

StackWise

Plus

24X1G POE 24X1G POE

Two Stack

Cables

8 PortPHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY


Catalyst 3750 Overview3750v2 & 3750G

3750 and 3750-X Main Architectural Differences:

3750 Does not have a second tier switch fabric like the 3750-Xand can not locally switch without sending packets on the ring

3750 has external TCAMs

All port-ASIC are part of the Stackwise internal ring!

3750 only runs in StackWise mode – 32G

2 Stack

Cables

Ports

Port ASIC

TCAM

SRAM

SDRAM

CPU

Stack PHY

Flash

Serial

Port ASIC

TCAM

SRAM

Port ASIC

TCAM

SRAM

POE POE POE

Ports Ports

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY

8 Port

PHY

8 PortPHY

8 PortPHY


Catalyst Ring View3750v2 and 3750G

Physically, the ring is a series of port-ASICs strung together by stack cables

Two Stack

Cables

P

H

Y

Port ASIC

TCAM

SRAM

SDRAM

CPU

Stack PHY

Flash

Serial

Port ASIC

TCAM

SRAM

Port ASIC

TCAM

SRAM

Stack PHY

Stack PHYPort ASIC

CPU

Port ASIC Port ASIC Port ASIC

Port ASIC Port ASIC

CPU

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y


2 Stack

Cables

Ports

Port ASIC

TCAM

SRAM

SDRAM

CPU

Stack PHY

Flash

Serial

Port ASIC

TCAM

SRAM

Port ASIC

TCAM

SRAM

POE POE POE

Ports Ports

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY

8 Port

PHY

8 PortPHY

8 PortPHY

MACPort 1

MACPort 2

MACPort 4

MACPort 3

MACPort 16

TXTQueues

ForwardingController

RCVFIFO

TXTFIFO

RCVBuffer

TXTBuffer

ToCPU

FromRing

MACPort 5

TCAM SRAM

ToRing

Catalyst 3750 Asic Packet Flow3750v2 & 3750G

1 or 2 buffers

While Fwd Ctrl

reads 200 bytes,

lookup, pre-pend

24byte header

Frame may have multiple destination.

Fwd Cntrl decides

who receives a copy or send back on

Sneak path.


Architectural DifferencesWhat’s added to Catalyst 3750X

Catalyst 3750-X

Switch fabric assumes forwarding function and allows for local switching saving BW on the stack ring.

Higher density port-ASIC

Enhanced Ring protocol, DLAP (64Gbps) Stackwise Plus – backwards compatible with Stackwise (32G)

Line rate / Non-blocking architecture (No oversubscription)

Stackpower instrumentation for flexible power management and efficiency!

PoE+ support backwards compatible with PoE and enhanced PoE

Hardware based link encryption

Out-of-band management port, USB and RJ45 console ports

Full IPv6 support in HW (no compression)

P

H

Y

Port ASIC

TCAM

SRAM

SDRAM

Processor

Stack

PHY

Flash

Serial

Port ASIC

TCAM

SRAM

Port ASIC

TCAM

SRAM

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

Port ASIC

TCAM

SRAM

SDRAM

Processor

Stack

PHY

Flash

Serial

Port ASIC

TCAM

SRAM

Port ASIC

TCAM

SRAM

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

P

H

Y

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

24X1G POE 24X1G POE

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

24X1G POE 24X1G POE

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY

SDRAM

CPU

Stack PHY

Flash

Serial

Port

ASICPort

ASIC

Port

ASIC

Switch Fabric

Dual Mode PHY

10/100

2X10G or

4X1G12X1G 12X1G12X1G 12X1G

24X1G POE 24X1G POE

8 Port

PHY

8 Port

PHY

8 Port

PHY8 Port

PHY

8 Port

PHY

8 Port

PHY


Architecture OverviewCatalyst 3560E-12SD

A Port-ASIC handles traffic for twelve 1Gig SFP Ports

The other Port-ASIC handles traffic for two 10Gig Ports or four 1Gig SFP Ports

Point to Point Stackwise

Rings. DLAP-PP mode.

Stackwise 32G

Two Bidirectional ring

16G each

DDR SDRAM

FLASH

CPU

Switch Fabric

Port-ASIC1

Port-ASIC2

FRUPS

FRU

FANFRUPS Serial

10/100

X2

X2

X2-Phy

Four SFP Two XAUI

1 12…...…..

12 SFP

Supervisor Ring


Architecture OverviewCatalyst 3560E-12D (10G aggregator)

Three switch ASIC and three internal rings make up the switch fabric

Each Port-ASIC switches traffic for two 10G Ports.Each Switch ASIC switches traffic for two Port-ASIC

Switch Fabric 3Switch Fabric 1

Port-ASIC1

Port-ASIC2

Port-ASIC3

Port-ASIC4

Port-ASIC5

Port-ASIC6

1 2 3 4 5 6 7 8 9 10 11 12

10G Ports 1 - 12

Switch Fabric 2Switch Fabric


Traffic PatternsLocal Switching

Non-blocking wire rate for all traffic between both Port-ASIC; that is 20G bidirectional traffic

Traffic between any 4 ports on the

same Switch ASIC is line-rate.

All Local traffic from 10G ports goes through the Switch Fabric via the Port-ASIC.

Port-ASIC2

Port-ASIC1

Adequate bandwidth for two 10-Gbps ports at line rate

10-Gbps is the available bandwidth from each port to the Port-ASIC

X2 X2 X2 X2

Switch Fabric

Switch Fabric 3Switch Fabric 1

Switch Fabric 2Switch Fabric

Port-ASIC2

Port-ASIC2

Port-ASIC1

Port-ASIC1

Adequate bandwidth for two 10-Gbps ports at line rate

10-Gbps is the available bandwidth from each port to the Port-ASIC

X2 X2 X2 X2

Stackwise point to point


QoS Model

Summary

Switch Differences

Hardware Overview


StackPower


Packet Walks

Agenda


Allows access to all switches with a single IP address

Provides the means to manage the stack via CLI or MIB

Can connect all switches in a physical ring topology

Traffic flows in either direction of the ring, some Resiliency

Automatic Master selection & backup 1:N

Automatic IOS versioning and Update!

Automatic configuration of new members

Automatic unit replacement (configuration of old switch retained)

Statefull switch over in case of master failures

Ring resiliency similar to FDDI, provides HA and Resiliency

Sub-millisecond Master failover

Smart Multicast

Cross-stack features (Etherchannel and QoS)

What is a Stackable switch?


Added a New State in Stackwise-MIB OID: cswSwitchState

waiting(1), Waiting for a limited time on other switches in the stack to come online.

progressing(2), Master election or mismatch checks in progress.

added(3), The switch is added to the stack.

ready(4), The switch is operational.

sdmMismatch(5), The SDM template configured on the master is not supported by the new member.

verMismatch(6), IOS version on the master is different from the IOS version running on this member.

featureMismatch(7), Some of the features configured on the master are not supported on this member

newMasterInit(8), Waiting for the new master to finish initialization after master switchover (Master Re-Init)

provisioned(9), The switch is not an active member of the stack.

invalid(10) The switch's state machine is in an invalid state.

Removed(11) The switch is removed from the stack."


Recent Additions Stackwise-MIB

Added status of the Power stack!

Stackpower mode, Type, Members, and Name

Added cswStackPowerStatusGroup, cswStackPowerSwitchStatusGroup, and cswStackPowerNotificationGroup.

Enhancements will continue which might imply the creation of a new MIB for Stackpower!

StackPower


What is StackWise & How resilient is it?

It is a logical and physical ring architecture of the Catalyst 3k

The Stack ring comprises two 16 Gbps counter-rotating rings

Similar to FDDI media access protocol (synchronous and asynchronous)

Data on both rings when fully connected:

Stackwise 32 Gbps – HTPP

Stackwise Plus 64 Gbps – DLAP

Loopbacks provide healing as in FDDI

The Stack Ring is the switching fabric (Legacy Catalyst 3750 and V2)

All Port ASICs are on the ring and all frames are switched via the Stack

The Stack Ring only interconnects the individual Switch Fabrics (E-Series and X-Series switches ONLY)


StackWise Rings

Two counter-rotating rings

Eight TX/RCV pairs per ring

16 channels per ring, 8 TX, 8 RCV

2.5 Gbps per channel

8B/10B encoding

every ten bits sent, eight bits are data and two bits are overhead

Total bandwidth:

Stackwise (HTPP) 32 Gbps

Stackwise Plus (DLAP) 64Gbps

(Electrically is 32Gbps)

StackWise

Rings/Cable


Stack Cable1

TXT/RCVPairs

Trace

Stack Cable2

16 Gbps 16 Gbps16 Gbps 16 Gbps

Understanding the Stack Ring Speed

16 Channels x 2.5 Gbps x 8B/10B = 32Gbps

Or Two bidirectional 16 Gbps per cable = 32Gbps

Or Two Rings running at 16Gpbs each = 32Gbps


Stackwise Vs. Stackwise PlusSpatial Reuse

No Spatial Reuse

(Source Strip)

3750 StackWiseOnly 2 Flows

Access-based tokens

Spatial Reuse

(Destination Strip)

3750-X StackWise PlusUp to N by 2 Simultaneous Flows

Credit-based Tokens

Note: These are packets not tokens. There is only 1 token per ring.

Stackwise

32 Gbps

Stackwise Plus

N by 32 Gpbs


1st Gen (Stackwise)• Ring access controlled by Token

• Only one node can transmit at a time

• Source strips packets

2nd Gen (Stackwise Plus)• Ring access controlled by Credit

• Multiple nodes can transmit simultaneously (Spatial Re-use)

• Destination strips unicast packets and returns a small Ack (16bits)

• Token is used to distribute asynchronous Credit

• Backwards compatible with 1st Gen

Stackwise and Stackwise PlusProtocol Enhancement


Port ASICPort ASICPort ASIC



Switch Fabric

Switch Fabric

Switch Fabric

Loops

37503750-X

Ring Healing

The Switch Fabric or Port ASIC closest to cable detects link downCriteria is coding violations in a period of time

Loss of at most one packet that was being transmitted when ring broke

Just microseconds for hardware to detect failure

Each switch signals a bad link to stack its partner

Both ends of the cable loop back on themselves

Loop


FlexStack Overview


Not a ring Architecture – Hop by Hop

Local switching support for unicast packets

Proprietary header – 38 Bytes pre-pended on stack bound packets

Packet path determined using ―SPF‖ like algorithm

All members of the stack see the unknown Unicast, Broadcast, and Multicast packets

Two dedicated Egress Queues for the stack ports

Queue 5 - FlexStack Protocol packets

Queue 6 - Inter-member communication

FlexStack on the Catalyst 2960-SNew stacking mechanism


Every Stack port is active and forwarding

Except in a 2 member stack

FlexStack Discovers the topology (who’s connected to who)

Builds a ―drop table‖ based on a ―SPF like‖ algorithm

Determines the passive link for every stack member

―Passive link‖ is different for every stack member

Passive Link prevents BCAST storms by dropping packets

Packets are dropped based on source member

Source member = member the packet ingressed on.

Passive Link as far from source member as possible

Packet drops are implemented on Egress & not counted

Counted only if transmitted or dropped due to UPB congestion

FlexStack ConceptsDrop Table & Passive Link (stack ports)


Stack Link Neighbor Table

The Drop Table & “Passive Link”Stacking ports – Not uplinks

4321

22 21

1 1 1

Passive links – see drop table

Drop table

C2960S#show switch neighbors

Switch # Port 1 Port 2

1 2 4

2 3 1

3 4 2

4 1 3

Packet Ingress Member #Switch /

stack port 1 2 3 4

Port 1-1 BLK

Port 1-2 BLK

Port 2-1 BLK

Port 2-2 BLK

Port 3-1 BLK

Port 3-2 BLK

Port 4-1 BLK

Port 4-2 BLK

• Determines the Passive links

• Passive links are not too Passive!

• Packets are dropped upon ingress into a

stack port

How to read it:

1. First find the ingress switch: Source

member

2. Move down and find the BLK ports for that

member.

3. Each member has a different Passive Link


Packet flows in C2960-S stack are hop by hop.

L2 Destination type: Unknown, MCAST, BCAST all the same

Drop Table does not fwd packet between member 3 & 4

C2960-S FlexStack Packet Flow, BCAST

Member 1

Member 4

Member 3

Member 2

Bcast Packet

ingresses member 1

BCAST packet egresses

on all interfaces FWDing

on that vlan for all

members

Passive Link for

Switch 1 prevents

Fwd of packet between

members 2 & 3


2960-S FlexStackEase of Use

3750-X StackWise PlusEase of Use and High Availability

Device Limit 4 units 9 units

Stack Bandwidth 20G 64G

Architecture HW Drop Table Ring (Destination stripping)

Dynamic Ring Load Balancing

No Yes

Stack Convergence 1-2 seconds Few milliseconds

Stack QoS Applied hop by hop Applied on ingress

Management Single IP address, SNMP, SYSLOG Single IP address, SNMP, SYSLOG

ConfigurationSingle config and CLI, auto image and

config updateSingle config and CLI, auto image and

config update

Show and Debug Commands

Unified Unified

Single Forwarding andControl Plane

Synchronize ARP, MAC Address, IGMP, VLAN tables

Synchronize ARP, MAC Address, IGMP, VLAN, Routing tables

Cross-Stack Features Yes Yes

Single Bridge-ID Yes Yes

Preprovison members Yes Yes

Redundancy Stack master 1:N redundancy Stack master 1:N redundancy

Easy member replacement Yes Yes

FlexStack Vs. StackWise Plus


Summary

Switch Differences

Hardware Overview


StackPower


QoS Model

Packet Walks

Agenda


Stackwise Plus and Local switching

• With StackWise, locally destined packets must traverse the entire stack ring.

• With StackWise Plus, whether in a homogeneous or mixed-hardware stack, locally destined packets on an ―E‖ or ―X‖ series switch are never put on the stack ring.

StackWise StackWise

Plus

Local

Switching


3750 Unicast Packet WalkSource strip

All types of packets are passed all the way around the ring, copied at the destination(s) and returned to the sender for stripping

All packets are sent to the stack ring, the Port ASICs can not locally switch traffic

Source

Destination

Source

Destination

Packet

Port ASIC Port ASICPort ASIC



1. Forward To the Stack

2. Copy Packet by Dest. Port-

ASIC

3. Pass Packet to Dest. port

4. Original Packet rotates around the ring

5. Src Removes Packet off the

ring


Port ASIC Port ASIC Port ASIC

Switch Fabric

3750X Unicast Packet WalkLocally Switched (Stacked or standalone switch)

The packet is sent to the switch Fabric and locally switched to the destination Port ASIC

Simple switching with, no ACK necessary

Does not disrupt the Stack rings

Source

Destination

Packet

Packet is locally switched. Never get forwarded to Stackwise rings


Switch Fabric

The Source Port ASIC sends the packet to the Source Switch Fabric and it is switched to the Destination Switch Fabric

The Destination Switch Fabric removes the packet and sends a 16 bit ACK

The Originating Switch Fabric receives and removes the ACK

3750X Unicast Packet WalkDestination across the stack – Destination strip


Switch Fabric


Switch Fabric


Source

Destination

Packet

ACK

1. Forward To the

Stack ring

2. Copies packet – sends it to port-ASIC

3. Removes packet off the

stack ring

4. Send 16 bits ACK

5. Remove the ACK


The Switch Fabrics with multicast ports in that group copy the packet

The originating Switch Fabric removes the packet from the ring

Note: There is only one packet on the ring per multicast flow, replication only occurs at the local level

Note: if the sender and all of the receivers are on the same switch no packets are sent to the ring

Smart Multicast Packet WalkAll Catalyst 3K models

Source

Destination

Source

Destination

Packet




Switch Fabric

Switch Fabric

Switch Fabric

1. Multicast Packet Must forward to the stack ring!

2. Copy Multicast Packet: forward to the stack ring and to local port-ASICs

3. Replicate Packet and forward to the

port-ASICs that have listeners

5. Original Multicast Packet continues on the ring in case

there are more listeners in the stack.

4. Replicate in case of multiple

listeners

6. Remove Packet off the ring.Dest. Strip.


Switch Differences

Hardware Overview


StackPower


QoS Model

Summary

Packet Walks

Agenda


Aggregates and shares available input power capacity in a Stack

Flexible arrangement of power supplies in a stack

Up to 8.8Kw in a power stack of 4 switches (ring topology)

Up to 22Kw in a power stack of 9 switches (Star topology using an XPS 2200)

Stackpower decouples a Power supply from its physical location in a switch/stack!

Provides RPS functionality (Zero-footprint RPS)

Intelligent Load shedding

Independent from Stackwise/Stackwise Plus

StackPower Overview


StackPower Modes of OperationPower Share and Redundant Modes

StackPower operates in two modes:

Power share

Loose or Strict mode

Redundant

Loose or Strict mode

Up to four switches can be participate in a power stack

More than one power stack within one Data stack (Stackwise Plus)


All available input power is allocated, no reservation is made!

Treats all input power as one big power supply

No power reserved for PS failures

Allows for a negative power budget (Lose mode)

Power share ModeDefault

•A

•B

•A•B

•A•B

•B

•A

1100w

0w

0w

1100w

StackPower ring

500w

500w

500w

500w

Available Pwr Allocated Pwr Unused Pwr

2,200 W 2,000 W 200 W


Load sharing along with redundancy

Available power – reserved power = Power to be shared

Reserves 1 power supply worth of power from the budget

In mixed PS types, the largest PS capacity is reserved

Redundant ModeZero-footprint RPS

B

A

BA

A

A

B

1,100w 0w

500w

500w

500w

500w

B

1,100w

Reserved Power

1,100w

Available Allocated Unused RESERVED

3,300 W 2,000 W 200W 1,100 W


Lost PS or

Power source

Shed Load

Dropped PD

Lost PS or

Power source

Lost Shed Load

another PS

Dropped PD

Loose and Strict modesControl the behavior of Load shed

Loose mode allows for a negative power budget

Strict mode sheds load as soon as the power budget goes below the Allocated power level

BUDGETAvailable Power Pool

ALLOCATED CommittedPower

ACTUAL Drawn Power

BUDGET Available Power Pool


ACTUAL Drawn Power

Power-sharing Strict modePower-sharing Loose mode Default


Switch & Port PriorityHardware register per port/switch

Hardware uses a register to group ports in a High or Low priority group for each switch

All ports are part of the Low priority group by default

Stackpower has 27 priority levels

Default priority per group can be re-programmed

Users may re-program the priority level for the group

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Default StackPower Priorities

Switches High Priority Group Low Priority Group


More Low Prio 27

Power 26

Loss 25

24

23 Turn off all PD in the

22 low priority Group

21

20

19

18

17

16

15

14 High Priority Group

13

12

11

10

9

8

7

6

5 Switch priority

4

3

2

High Prio 1

Load

Shedding

Low Prio 27

26

25

24

23 Low Priority Group

22

21

20

19

18

17

16

15


13

12

11

10

9

8

7

6

5 Switch priority

4

3

2

High Prio 1

Load

Shedding

Power loss

Negative

Budget

Low Prio 27

Loose mode 26

25

24


22

21

20

19

18

17

16

15


13

12

11

10

9

8

7

6

5 Switch priority

4

3

2

High Prio 1

Load

Shedding

Low Prio 27

26

25

24


22 low priority Group

21

20

19

More 18

Power 17

Loss 16

15


13 High priority Group

12

11

10

9

8

7

6

5 Switch priority

4

3

2

High Prio 1

Load

Shedding

Power loss

Strict Mode Low Prio 27

26

25

24


22

21

20

19

18

17

16

15


13

12

11

10

9

8

7

6

5 Switch priority

4

3

2

High Prio 1

Load

Shedding

Priority based Load sheddingPredictable behavior during power failures

A group priority can Not be higher than ―the‖ priority of the switch

A switch priority can be lower than a group priority on another switch!

Configure Priorities:

Stack-power switch <1-9>

power-priority switch <1-27>

power-priority High <1-27>

power-priority Low <1-27>

Display switch priorities:

Show stack-power

Configure Port Group priorities:

interface GigabitEthernet2/0/1

power inline port priority high/low

Display port Group priorities:

Show power inline Priority

BUDGET Available Power Pool


ACTUALDrawn Power


Valid Stackpower deployments

Either a Ring or a Star topology – that is 4 or 9 switches!

Ring – a maximum of 4 switches in a Stackpower

Star – up to 9 switches, attached to an XPS 2200

A Data stack (Stackwise) can span over two or more power stacks regardless of the topology

A Power stack can span over two or data stacks but it is Not Recommended!

StackPower 1 = 3 switches

One Data Stack(Stackwise)9 switches StackPower 2 = 3 switches

StackPower 3 = 3 switches


Nothing will catch fire nor explode

What is the issue?

Stackpower reports all power information to the data stack.

If you have two data stack masters, both receive the exact same information about available power resources!

If you are not careful, you can oversubscribe the power pool and cause power outages and switch reload!

What If I want to span a Power stack across two Data stacks?.....You can!

One Power stack(StackPower)

4 switches

Data stack 1 = 2 switches

Data stack 2 = 2 switches


Best Practice Balance Power supplies across the stack

Total Input Power = 5,400w

Total Output Power = 4,400w

The right half generates only 20A but consumes 80A

Stackpower rated for ~40A

In failure scenario, Stackpower could be oversubscribed; console messages will warn about the condition and Intelligent load shed will occur.

500w

500w

A B

1,100w

1,100w

A B

1,100w

1,100w

A B

2,000w

A B

2,000w

200w

200w

X

30 A

60 A

30 A

Recommendation:

1. Balance PS across all systems, and

2. insist on filling up PS slot A on every switch in

the stack, before using slot B on any switch!


The XPS 2200 is a next generation Power system

Provides Power-sharing and RPS functionality concurrently

When used with the 3750-X it provides StackPower functionality to all the stack members including power supply redundancy

When used with the 3560-X it provides RPS functionality

Protects up to 9 switches – stackable, standalone, or mixed

XPS supports up to two power supplies and redundant fans

Offers full PoE+ redundancy to a 48-port switch

That is 30W each on all 48 ports or 1440W of PoE+ plus system power.

eXpandable Power System – XPS 2200StackPower & RPS Functionality


The XPS supports 3 modes of operation:

Power share, Redundant, and RPS modes

Mixed mode, that is, two modes combined in case there mixed type of switches attached to the XPS.

I.E. Cat3750X and Cat3560X

Catalyst 3750X: Stackpower functionality

Supports all Power sharing modes:

Power-share, Redundant, RPS modes

Catalyst 3560X: RPS functionality ONLY

Only Traditional RPS mode

One to one, that is, one XPS Power supply to one switch!

Operations: Power modesXPS 2200


Sw4 PS

350W

Sw3 PS 1100W

Sw2 PS 715W

Sw1 PS: 440W

DC

Cisco StackPower

Sw4 PS

350W

Sw3 PS 1100W

Sw2 PS 715W

Sw1 PS: 440W

DC

Cisco StackPower

XPS Power

supply A

XPS Power

supply B

XPS – Power-Sharing FunctionalityStackPower – Power-share & Redundant modesCatalyst 3750X ONLY

ooo...Switch 1

Cat 3750X

Switch 9

Cat3750X

ReservedPower

• Including power reservation.

• XPS allows for a larger power pool:

Stackpower of up to 9 switches and

20 power supplies.

•XPS automatically detects the switch

and shares power among all devices

• All features of Stackpower are available

XX

X

Power Bus


Sw4 PS

350W

Sw3 PS 1100W

Sw2 PS 715W

Sw1 PS: 440W

DC

Cisco StackPow

XPS Power

supply A

XPS Power

supply B

XPS – RPS FunctionalityPower Redundancy OnlyCatalyst 3560X

ooo...Switch 1

Cat 3560X

Switch 9

Cat3560X

X X

X X

X• No StackPower for Cat3560X.

• XPS detects the switch type and can serve RPS

functionality to non-Stackable switches.

• Power redundancy is restricted to One Power

supply to one switch.

• Maximum of two active backups concurrently.


Trend to translate a switch’s power consumption into Power dissipation… Not quite the same in the wiring closet..!

Datasheet provides Switch power draw under different conditions

No other power use or waste is considered

Power Consumption ≠ Power Dissipation (in the wiring closet)

Total Power consumption includes:

Switch board power draw (ASIC and components) found in a datasheet

POE or POE+ (if any)

Power supply Loss (Power supply inefficiency and cost of generating POE)

Total Power Consumption by a switch:

Power Consumption = Switch Power Draw + POE draw + Power Supply Loss

Power ConsumptionIn a wiring closet


All drawn power must be dissipated…..there is no other way!

POE power is dissipated outside of the wiring closet; hence:

Power Dissipation = Switch Power Consumption + Power Supply Loss

Power supply loss includes Inefficiency and cost of generating POE

Power Dissipation in Watts (Wiring Closet):

= Switch Power Consumption + 5% x Drawn_PoE + Power supply (Loss)

Power Dissipation in BTU/hr

Convert to BUT/HR = Watts X 3.412

See whitepaper on CCO:

―Calculating Power for Stackpower and the Catalyst 3750X‖

Power DissipationIn a wiring closet


Switch Differences

Hardware Overview


Packet Walks


QoS Model

Summary

StackPower

Agenda


A Switch stack is Not a series of switches connected in a ring topology; That is a pile of switches!

A Switch stack implies a redundant physical topology plus an intelligent control plane & management!

During formation of a stack, a master is elected

All switches have the ability to be stack master—no configuration is required – Intelligent stack!

The stack master can be selected by assigning a user-configurable priority 1 through 15, 15 being the highest

The master can be identified via CLI, MIB, orLED display

1:N master redundancy

All non-master switches are called members

Stack Master and Members


1) The stack (or switch) whose master has the higher user configurable mastership priority 1–15

2) The stack (or switch) whose master is not using the default configuration

3) The stack (or switch) whose master has the higher software priority

Cryptographic IP Services

Cryptographic IP Base

Cryptographic LAN Base

4) The switch or stack whose master has the lowest MAC address

Stack Master Election Criteria


Switch Priority for Master RoleDefault Is 1, Don’t Participate Is 0

Switch (config)# switch 3 priority 10

Switch (config)# exit

Switch# show switch

Switch# Role Mac Address Priority State---------------------------------------------------------------------------------1 Member 000a.fdfd.0100 5 Ready 2 Member 000a.fdab.0100 5 Ready3 Master 000a.fd22.0100 10 Ready4 Member 0003.fd63.9c00 5 Ready


A Stack Master Can Change If:

The stack master fails or reboots

The stack master is removed from the switch stack

The stack master is power cycled or powered off

There is a Stack Merge

Stack merge occurs when a new switch is powered up before being connected to the stack cables, or when two cables are disconnected from the stack

When the Stack Master Changes?


Functions of the Stack Master

The Stack Master:

Controls all centralized functions

Builds and propagates the L3 FIB

Manages and Propagates the configuration file to the stack

Controls the console

Controls the CDP neighbor table

Controls the VLAN database

Upgrades the stack

ConfigFIBIOS

Config

FIB

IOS

Config

FIB

IOS


Automatic Switch IDNo need for configuration

Member switches are assigned switch numbers automatically

Valid switch numbers are 1 through 9 – Switch ID does not reflect physical location in the stack

Switch numbers are ―sticky‖ – Switches remember their ID even when removed off the stack

The user has the ability to pre-assign or renumber the switch via CLI

The switch number can be shown by using the Mode button, ―STACK‖ LED

Switch(config)# set switch number 4

Switch(config)# exit

Switch # write mem


Centralized and Distributed Functions

Centralized functionsThose that reside on the master node

Those that are forwarded to the master node

Those that are controlled or synchronized by the master node

Distributed functionsThose that are performed locally by each node

These functions are synchronized or updated between the nodes

Master

Master


CPU

CPU

CPU

TCAMs

TCAMs

TCAMs

MAC Address ManagementDistributed MAC learning

Stack members learn MAC addresses and updates TCAM entries

System synchronizes MAC address tables across the stack

How it is distributed:

A switch learns an address and sends a message to other switches in the stack

Learning an address that was previously learned on a different port (either same or different switch) is considered as move

MAC B

MAC A


CPU

CPU

CPU

STPDistributed

Each switch in the stack runs its own spanning tree instance per VLAN

Each switches will use the same bridge-id

Each switch process its own BPDUs

Show commands show spanning tree as a single entity

Stacking ports are never blocked

All packets on the ring have the internal ring header; Therefore, even broadcast packets are source stripped and do not continuously recirculate.

Supports Cisco enhancements, like Uplink-fast, Backbone-fast, Port-fast, Root-guard, BPDU-guard, etc. are supported with no impact.

There is support for 128 instances of STP per node/stack

BPDU

BPDU


CDPCentralized

CDP is implemented using centralized model

The master will maintain CDP neighbor table and the neighbor tables will be empty on member nodes

Upon a master switchover, a new master will build the CDP neighbor table

Master


Cross Stack Etherchannel/LACP Centralized

An LACP-based Etherchannel can be formed with member ports from one or more switches in the stack

Etherchannel control, not forwarding, is performed by the master node

Benefits:

In addition to port aggregation, load-balance, and link redundancy; switch-level redundancy is provided

Single Channel Group


VLAN DatabaseCentralized

All switches in the stack build from same VLAN database

Members download VLAN database from master during initialization

They are synchronized over the stack ports

The stack supports all 3 VLAN Trunking Protocol (VTP) modes: server, client and transparent modes

1024 VLANs; 4K VLAN IDs are supported

TCAMs

TCAMs

TCAMs

Master


Ping 30.0.0.5

Ping 20.0.0.5

Ping 10.0.0.5

10.0.0.15 / 24

20.0.0.15 / 24

30.0.0.15 / 2430.0.0.5 / 24

20.0.0.5 / 24

10.0.0.5 / 24

Master Switch

IP Stack

Master

IP Stack

IP Stack

Cross Stack IP Host Centralized

The IP stack is active only on stack master

All IP applications like ICMP, TFTP, FTP, HTTP, SNMP, etc. are handled on the stack master irrespective of, which switch the L3 interface is connected to.


FIBs/TCAMsRP/RIB

Master

FIBs/TCAMs

FIBs/TCAMs

L3 Routing Centralized

The Master is the route processor and builds the Routing Information Base (RIB)

All Switches have a mirror copy of the Forwarding Information Base (FIB)

Routing protocols include Static, RIPv1and v2, OSPF, EIGRP, BGP, PIM-SM/DM, DVMRP, HSRP

The Catalyst 3750 uses cross stack equal cost routing and must be centralized

The Stack appears as a single router to the world because it is!

Policy Based (PBR), IPv4 and IPv6 Routing in hardware

Non Stop Forwarding (NSF) Aware and NSF Capable


Configuration Management

Master:

Copies of the startup and running config files are kept on all members in the stack

The current running-config is synched from the master to all members

On a switchover, the new master re-applies the running-config so that all switches are in sync

Member:

Keeps a copy of startup and running config at all times

On boot-up waits for config file from master and parses it

Config

Config

Config


Switch AdditionExample

The stack has three members—with numbers 1, 2, 3

A new switch with an existing #3 is added to the stack

The new switch detects a conflict, and loses, based on the rules used for numbering (ID).

It is assigned the #4 and reloads switch #4

All configuration commands in the config file which apply to interfaces 4/0/* apply to the new switch

Switch #2

Switch #3

Master #1

Switch #4


Master #1

Switch #2

Switch #3

Switch PreprovisioningExample

Create a provision Switch #4

(Shadow).

Enter the port configuration of

the New Switch.

Set the Switch Number (#4)

ConfigConfig

Switch #4


Preprovisioning a Switch

Switch(config)# switch 4 provision WS-C3750X-48P

Switch(config)# exit

Switch# write mem

Switch# show running-config | include switch 4

Switch 4 provision ws-c3750x-48p

!

!


!


!


<output truncated>


Switch Removal

The stack has three members — 1, 2, 3

Switch #3 is removed or powered down

Neighbor loss is detected by Switch #1 and Switch #2

Layer 2 and Layer 3 convergence may need

to happen

Now there is a stack of two switches—Switch #1 and Switch #2

Switch#1 is still the master

Switch #1 is removed or powered down

Switch #2 takes over as master

Layer 2 and Layer 3 convergence may need to happen

Now there is a stack of one switch—#2 which is the master

Master #2

Master #1

Switch #2

Switch #3


Replacing a Switch

Replacing a Failed Switch:

For example, the failed switch is a Cisco Catalyst WS-C3750E-48TD

If replaced by another Cisco Catalyst WS-C3750E-48TD, the new switch will receive the port-level configuration of the original unit

If replaced by a different switch, the original configuration is lost and the new switch receives all stack global configuration

ConfigConfig


Types of Stack Mismatch

Homogeneous Stack: 3750 or 3750E/X:

Version Mismatch:

IOS revision level and feature set i.e. LAN Base, IP Base, and IP Services

SDM Mismatch:

All members of the stack must run the same SDM template as the master

Version Mismatch has priority over SDM mismatch

Hardware Mixed Stack: 3750 and 3750E/X:

Same as above

Feature Mismatch

Hardware features (POE, Jumbo frame routing)

3750

3750-X

3750-E

3750-E

3750-X

3750-E

3750-E


Version MismatchGets resolved first

Master and new member are not running the same IOS feature set:

LAN Base vs. IP Base / IP Services

Proper IOS image (rev level) was not found

Must individually upgrade IOS version

Use the multiple file download option for HW Mixed stack

Use the TFTP assistance option

3750 Base

3750-X Universal

3750-E Universal

3750-E Universal

3750 IP Base

3750 IP Base

3750 IP Services


The Catalyst 3750-E switch supports only the desktop Switch Database Management (SDM) templates.

The Catalyst 3750 switch supports either the Desktop or Aggregator SDM templates—but a stack can not run a mix of SDM templates.

All stack members use the SDM template configured on the stack master

In a mixed hardware stack

A Version mismatch has priority and it gets resolved first

All other switches trying to join this stack enter SDM-mismatch mode

If a Catalyst 3750 stack master is using an Aggregator template, then a Catalyst 3750-E switch cannot join the stack

In this scenario, Only Catalyst 3750 aggregator switches can be stack members

SDM MismatchHardware Compatibility and SDM Mismatch Mode


This Is a Mismatch of Hardware Capabilities in a Stack:

A stack of ―G‖ or ―E/X‖ series switches running interdependentfeatures such as Jumbo frame routing or more than 32 HSRP groups,

And

A switch/stack of Cat3750 switches attempting to join the stack and not able to support the advanced Hardware capabilities of an ―E‖ or ―X‖ series switch

Caveat: If an ―E‖ or ―X‖ series switch in feature mismatch mode is reloaded, then the switch will be able to join the stack because it will ignore the incompatible IOS configuration commands as it boots up.

Feature Mismatch (Mixed Hardware Stack)Interdependent features – globally enabled


Port level features specific on the Catalyst 3750X & 3750E can be deployed in a HW mixed stack (different switch family types)

For example:

HW Encryption on the X-series

Egress shaping

Port + IP ACL on a port

POE+

Interdependent or System-based features can Only be deployed on the same switch family type of a HW mixed stack

E and X Series are considered same family type but Not V2 nor G Series.

For example:

Jumbo frame routing

Unicast RPF

Feature Mismatch (Mixed Hardware Stack)Port level and Interdependent features


LAN Base StackException: No mixed IOS feature set

A form of Feature mismatch in a mixed Hardware stack

No HW Encryption, no Stackpower support

No mixed IOS feature set support for LAN Base

Catalyst 3750X models running LAN Base feature set can only stack among themselves

Common mistake…Don’t call TAC..!

Stacking LAN Base models with IP Base / IP Services


Automatic Upgrade involves two processes:

Auto-Upgrade and Auto-Advise

The auto-upgrade processes runs first and it consists of:

auto-copy process and auto-extract process

Auto-copy copies a running image of any stack member into a switch in VM mode

if this process fails, then:

Auto-extract searches through all FLASH devices for a TAR file suitable for the switch in VM mode

If auto-extract fails, Auto-Advice provides a recommendation on how to upgrade manually!

Recommend:

Store Universal and Reformation TAR images in the master and a backup master for auto-extract to work

Configure a url for last resort: (point to the image repository)

boot auto-download-sw tftp://10.1.1.15/images/fall06/c3750-universal-tar

Use to upgrade a mixed hardware stack:

archive download-sw /directory tftp://10.1.1.10/ c3750-ipservices-tar.122-35.SE.tar c3750e-universal-tar.122-35.SE2.tar

Stack IOS Upgrade Process


QoS Model

Switch Differences

Hardware Overview


Packet Walks


Summary

StackPower

Agenda


Cisco Catalyst 3750 Family QoS Model

Classification

• Inspect incoming

packets

• Assign QOS Label

to grouped packet

• Use ACL, or other

configuration to

determine QOS

labels

Policing

• Compares

incoming traffic

rate w/ configured

policer and

determine if

packet is IN or Out

of Profile.

• Either aggregate

or individual flow

basis

• 256 policers/ASIC

Marking

• Act on policer

decision

• Reclass or drop

out-of-profile

Egress Queue/

Schedule

Congestion

Control

• Four SRR queues/port shared

or shaped servicing

• One queue is configurable

for strict priority servicing

• WTD for congestion

control (three thresholds

per queue)

• Egress queue shaping

• Egress port rate limiting

Ingress Queue/

Schedule

Congestion

Control

• Two queues/port

ASIC shared

servicing

• One queue is

configurable for strict

priority servicing


control (three

thresholds per queue)

• SRR is performed

Policer

Policer

Policer

Policer

Marker

Marker

Marker

Marker

Classify

Input

Traffic

Queue 1

Queue 2

SRR

Sta

ckWise

Queue 1

Queue 2

Queue 3

Queue 4

SRR


Catalyst 3750 Control Plane Protection 16 Processor Hardware Queues

DoS protection via 16 CPU queues.

The workload is distributed to processors on each switch of the stack.

The stack ring reserves bandwidth for priority traffic

Bandwidth reservations on the ring ensure the CPU communication is not affected by data traffic.

These 16 processor queues are not configurable:

RPC, STP, IPC, Routing Protocol, L2 Protocol, Remote Console, SW Forwarding, Host, Broadcast, cbt-to-spt, IGMP Snooping, ICMP, Logging, RPF-fail, Dstats, CPU Heartbeat

…

Traffic to the CPU


A

Q2

Weight

2

Q1

Weight

1

Q3

Weight

3

Q4

Weight

4

Shaped SRR vs. Shared SRR

B

B

A

B

A A

Shaped Shared

Q2

Weight

2

Q1

Weight

1

Q3

Weight

3

Q4

Weight

4

A

B

A A

Shared Queuing drains queues more efficiently!

SRR Non-shared

SRR Shared

Packet Order

Wait Wait Wait

BB

CCD

A

Room for more traffic, draining the buffers!SRR Shared

Lesser weight queues sit idleand wait to transmit, even if

higher weight queues are empty

If higher weight queues are empty, lesser weight queues can continue

to send while the higher weightqueues are empty


Either Shaped SRR or Shared SRR is Good!

Shared SRR is used to get the maximum efficiency out of a queuing system, because unused time slots can be reused by busier queues; Unlike standard WRR.

Shaped SRR is used when one wants to shape a queue or set a hard limit on how much bandwidth a queue can use

Shaped SRR vs. Shared SRR

One can Shaped SRR one can shape queues within a port’s

overall shaped rate, and map traffic types to those queues

for shaping


Cisco Catalyst 3750 Weighted Tail DropFour Egress Qs identify 12 services!

WTD is a congestion-avoidance mechanism for managing the queue lengths and providing drop precedence for different traffic classifications

WTD is used at both, the Ingress queues or the Egress queues

User configurable thresholds determine when to drop certain types of packets

As a queue fills up, lower priority packets are dropped first

In this example, when the queue is 60% full, arriving packets marked with CoS0-5 are dropped

Thresholds can be set with DSCP or COS labels.

Only one Q is Displayed. All 4 Egress or 2 Ingress

QueuesCan Be Configured

Independently

100%

60%

40%

1000

600

400

0

CoS 6-7

CoS 4-5

CoS 0-3

Queue 1


Policer

Policer

Policer

Policer

Marker

Marker

Marker

Marker

Classify

Input

Traffic

Queue 1

Queue 2

Queue 3

Queue 4

SRR

Cisco Catalyst 2960S – No Ingress QueueQoS Model

Classification

• Inspect incoming

packets

• Assign QOS Label

to grouped packet

• Use ACL, or other

configuration to

determine QOS

labels

Policing

• Compares

incoming traffic

rate w/ configured

policer and

determine if

packet is IN or Out

of Profile.

• Either aggregate

or individual flow

basis

• 256 policers/ASIC

Marking

• Act on policer

decision

• Reclass or drop

out-of-profile

Egress Queue/

Schedule

Congestion

Control

• Four SRR queues/port shared

or shaped servicing

• One queue is configurable

for strict priority servicing


control (three thresholds

per queue)

• Egress queue shaping

• Egress port rate limiting

NO

Ingress Queues


Switch Differences

Hardware Overview


Packet Walks


QoS Model

StackPower

Summary

Agenda


The Differences between Catalysts 3K models

What is a stack?

Do I have 1 or 2 rings in my stack?

Is my stack redundant?

What is Flexstack, is it better than Stackwise?

What is StackPower?

Stackwise = 9 switches but Stackpower = 4 switches

How do I build my stack?

Can I mix any Catalyst 3k in one stack?

Can I mix any IOS feature set in one stack?

How does QoS work?

Questions Answered Today..!


Receive 25 Cisco Preferred Access points for each session evaluation you complete.

Give us your feedback and you could win fabulous prizes. Points are calculated on a daily basis. Winners will be notified by email after July 22nd.

Complete your session evaluation online now (open a browser through our wireless network to access our portal) or visit one of the Internet stations throughout the Convention Center.

Don’t forget to activate your Cisco Live and Networkers Virtual account for access to all session materials, communities, and on-demand and live activities throughout the year. Activate your account at any internet station or visit www.ciscolivevirtual.com.

Complete Your Online Session Evaluation

http://www.ciscolivevirtual.com/


Visit the Cisco Store for Related Titles

http://theciscostores.com

http://theciscostore.com/


Thank you.

Documents

Catalyst 3750 & 3560 Architectured2zmdbbm9feqrf.cloudfront.net/2011/las/pdf/BRKARC-3437.pdf · One ―Universal‖ IOS image contains all IOS features Licensing enables a specific