L2 and L3 Functions

TRAINING GUIDE

March 2014

Rev 1.0

Index

No Topic Page

1 VLAN 2

2 Inter-VLAN Routing 5

3 L2 Redundancy and Configuration 7

4 Link Aggregation 13

5 Multi-chassis trunking 16

6 Virtual router redundancy protocol enhanced 20

BROCADE COMMUNICATIONS TRAINING GUIDE

2

A. VLANs

VLAN is:

A subgroup within a local area network

A separate broadcast domain

A logical partitioning of a physical LAN into one or more Virtual LANs (VLANs)

Each VLAN has an ID

VLAN IDs (VID) can range from 1 4095

The default VLAN is 1

By default all interfaces belong to VLAN 1

VLAN 1 should only be used as a container for unused ports

VLAN without 802.1Q Tagging

Ports require dedicated uplinks for each VLAN between switches

There is no question where broadcast traffic went from port-to-port

VLAN - 802.1Q Tagging

VLAN tagging allows multiple VLANs to span switches over a single physical link

VLAN tagging is needed when a link is connected between any two switches carrying traffic from

multiple VLANs

In example below, Since both sides of the link must be configured for 802.1Q tagging, ports 4

and 14 are tagged so that they can be in multiple VLANs

The switch looks at the VLAN ID to determine which VLAN gets the forwarded frame


3

If a device is connected to a port in a single VLAN only, the port is untagged

Port-based VLAN

A port-based VLAN is a broadcast domain, composed of a subset of ports on a Brocade device

Traffic is bridged within a port-based VLAN and unknown unicasts, broadcasts and multicasts are

flooded to all the ports within the VLAN, except the incoming port

This is the most common type of VLAN

Create VLAN 10 and assign untagged ports 7 8 and tagged ports 14 15

SW-Switch(config)# vlan 10

SW-Switch(config-vlan-10)# untagged e 7 to 8

added untagged port ethe 7 to port-vlan 10

added untagged port ethe 8 to port-vlan 10

SW-Switch(config-vlan-10)# tagged e 14 to 15

added tagged port ethe 14 to port-vlan 10

added tagged port ethe 15 to port-vlan 10

Command show vlan will display all configured VLANs

FastIron(config)# show vlan

Total PORT-VLAN entries: 2

Maximum PORT-VLAN entries: 128


4

PORT-VLAN 1, Name DEFAULT-VLAN, Priority Normal, Spanning tree On

Untagged Ports: 1 2 3 5 6 8 9 10 11 12 15 16 17 18 19 20

Untagged Ports: 21 22 23 24 25 26

Tagged Ports: None

PORT-VLAN 2, Name [None], Priority Normal, Spanning tree On

Untagged Ports: 4 7 13

Tagged Ports: 14

Dual Mode Port

Configuring a tagged port as a dual-mode port allows it to accept and transmit both tagged

traffic and untagged traffic at the same time

Configuring a dual mode port:


SW-Switch(config-vlan-10)# tagged e 6 e 49

SW-Switch(config-vlan-10)# untagged e 34

SW-SW-Switch(config-vlan-10)# vlan 20

SW-SW-Switch(config-vlan-20)# tagged e 6 e 49

SW-SW-Switch(config-vlan-20)# int e 6

SW-Switch(config-if-e1000-6)# dual-mode 10

SW-Switch(config-if-e1000-6)# exit


5

B. Inter-VLAN Routing

Routing switch

Ports can be grouped together to form switched domains (L2 VLANs)

Virtual Ethernet Interfaces (VE) are created to route L3 traffic between VLANs

Switching among ports in a VLAN domain

Routing between VLANs

Configuring Routable VLANs

1. Configure port- based VLAN

2. Define Virtual Interface (VE)

3. Assign an IP address to the VE


SW-Switch(config-vlan-10)# untag ethernet 1/1 to 1/12

SW-Switch(config-vlan-10)# router-interface ve 10

SW-Switch(config-vlan-10)# interface ve10

SW-Switch(config-vif-10)# ip address 192.123.22.1/24

SW-Switch(config-vif-10)# vlan 20

SW-Switch(config-vlan-20)# untag ethernet 1/13 to 1/24

SW-Switch(config-vlan-20)# router-interface ve 20

SW-Switch(config-vlan-20)# interface ve20

SW-Switch(config-vif-20)# ip address 192.123.44.1/24


6

Show commands

SW-Switch#Show ip interface

SW-Switch#Show ip route

Summary

A VLAN is a logical partitioning of a physical LAN into one or more Virtual LANs (VLANs)

VLAN tagging allows multiple VLANs to span switches over a single physical link

Configuring a tagged port as a dual-mode port allows it to accept and transmit both tagged

traffic and untagged traffic at the same time


7

C. L2 Redundancy and Configuration

Brocade supports the following STP standards:

802.1D - Spanning Tree Protocol

802.1w - Rapid Spanning Tree (RSTP)

802.1s - Multiple Spanning Tree (MST)

Brocade supports the following STP enhancements:

Per-VLAN Spanning Tree

Single Instance Spanning Tree (SSTP)

Topology Group

STP

STP is defined in IEEE 802.1D

The spanning tree algorithm ensures a loop free topology by enabling a single path through any

physical arrangement of bridges

STP does the following:

Detects redundant links

Blocks redundant links

Allows for failover to redundant links

STP is enabled by default on Brocade Layer 2 code

STP is disabled by default on Brocade Layer 3 code

Without STP enabled, redundant links can cause endless loops, especially with broadcast traffic

Ethernet has no time out value on frames

With STP enabled, redundant links are blocked, and traffic is forwarded to its destination


8

802.1D Show Commands

Disabling and Changing Priority for STP

To disable STP globally:

SW-Switch(config)# no spanning-tree


9

To change bridge priority:

SW-Switch(config)# spanning-tree priority

Bridge priority value range is 1 - 65535

Default priority value is 32768

Per-VLAN Spanning Tree (PVST)

Each VLAN has its own:

Instance of STP

Root bridge

Set of bridge priorities

BPDUs

PVST - STP Load Sharing

PVST can be used to load share Layer 2 traffic by sending traffic from different VLANs onto

different physical links

Traffic from one VLAN can be forwarded over another VLAN without causing a loop

Fast Port Span

Allows faster convergence on ports that are attached to end stations

On by default in Brocade switches

End stations cannot cause forwarding loops, they can safely go through the state changes faster

than STP

VLAN 100 VLAN 201


10

Performs the convergence on these ports in four seconds

Two seconds for listening

Two seconds for learning

Used in 802.1D only

Fast Port Span is automatically disabled if the switch detects any of the following conditions on a

port:

a) It has an 802.1Q tag

b) It is a member of a LAG

c) The switch detects more than one MAC address on the port

d) The switch sees an STP BPDU coming in on it

Rapid Spanning Tree Protocol (RSTP) - IEEE 802.1w

802.1w is an enhancement to the 802.1D Spanning Tree Protocol

Convergence in 802.1w is not based on any timer values

It is based on the explicit handshakes between directly connected inter-switch links to

determine their role

Convergence time is less than 3 seconds in most cases

Root bridge failure detection in 1 hello time interval

Default hello time is 2 seconds

Ports should be configured as edge ports if they are attached to end devices

These edge ports transition directly to the forwarding state

Admin point-to-point ports should be configured for switch-to-switch connections

RSTP maintains a view of the topology, including redundant links

This avoids timeouts if the current forwarding ports were to fail or BPDUs were not

received on the root port


11

RSTP Configuration

To enable RSTP:

SW-Switch(config-vlan-2)# spanning-tree 802-1w

To define the priorities:

SW-Switch(config-vlan-2)# spanning-tree 802-1w priority 16

SW-Switch(config-vlan-2)# spanning-tree 802-1w e1/2 priority 16

To define port parameters:

SW-Switch(config-vlan-2)# span 802-1w e 1/4 admin-edge-port

SW-Switch(config-vlan-2)# span 802-1w e 1/2 admin-pt2pt-mac

Topology Groups

A topology group is a group of VLANs configured together and assigned a single, shared instance

of STP, RSTP, VSRP, or MRP

Topology groups simplify configuration and enhance scalability of L2 protocols by allowing the

use of a single instance of an L2 protocol on multiple VLANs

Each topology group has a master VLAN, where the STP settings are defined

All other VLANs in the topology group are added as members

A topology group is one way around the limitations of Per-VLAN Spanning Tree


12

Useful in the case where there are more VLANs than STP instances available

Topology groups are proprietary to Brocade Ethernet devices

Any STP configurations made in the master VLAN will be automatically applied to all member

VLANs

A VLAN may only be a member of a single topology group

To configure a topology group, first configure the VLANs:

SW-Switch(config)#vlan 10

SW-Switch(config-vlan-10)#tagged e1 to 4

SW-Switch(config-vlan-10)#vlan 20


SW-Switch(config-vlan-20)#vlan 30


Next, define the topology group:

SW-Switch(config)#topology-group 1

SW-Switch(config-topo-group-1)#master-vlan 10

SW-Switch(config-topo-group-1)#member-vlan 20

SW-Switch(config-topo-group-1)#member-vlan 30

Summary

The spanning tree algorithm ensures a loop free topology by enabling a single path through any

physical arrangement of bridges

BPDUs are messages exchanged between switches in a LAN or VLAN to form and maintain a

loop free topology

A path cost is the accumulated port cost from the root switch to the other switches in

the topology

Per-VLAN Spanning Tree can be used to load share Layer 2 traffic by sending traffic from

different VLANs onto different physical links

A topology group is a group of VLANs configured together and assigned a single, shared

instance of STP, RSTP, VSRP, or MRP


13

D. Link Aggregation

Trunking = Link Aggregation

Trunking is another term for Link Aggregation

A trunk is a group of physical ports between two switches that acts as one logical link

Brocade manuals will often refer to LAGs as trunks

Link Aggregation allows an administrator to combine multiple Ethernet links into a larger logical

trunk known as a Link Aggregation Group (LAG)

The switch treats the trunk as a single logical link

The physical links must all be the same speed and duplex setting and must connect to the same

adjacent switch

LAG requirements may vary for different platforms, such as the number of links in the LAG,

specific port boundaries, etc.

Always check what is supported at both ends

LAG Benefits

Increased bandwidth

Increased availability

Load-sharing

Sub-second failover to the remaining links in the LAG

Types of LAGs

There are two types of LAGs:

Static

Manually configured aggregate links containing multiple ports


14

Dynamic: (802.3ad Link Aggregation)

Dynamically created and managed LAGs using Link Aggregation Control Protocol

(LACP)

The only real difference between a static and a dynamic LAG is how they are formed; once

operational, they functionally the same

They also use the same load sharing methods

Configuring Static and Dynamic LAGs

All interface parameters in a LAG must match, including:

Port tag type (tagged/untagged)

Configured port speed1 and duplex

QoS priority

Brocade switches support the use of static and dynamic LAGs on the same device2

Can use only one type of LAG for any given port

lag "Controller2" dynamic id 2 ports ethernet 1/1/5 to 1/1/6 primary-port 1/1/5 deploy ! lag "MCT-ICL" static id 10 ports ethernet 1/1/7 ethernet 1/1/9 primary-port 1/1/7 deploy

Aggregate Link Keys

Every 802.3ad-enabled port has a key

The key identifies the ports that belong to the same LAG

Ports with the same key are called a Key Group

A default key is automatically assigned to an untagged port when link aggregation has been

enabled on it

Link aggregation keys must manually be configured for tagged ports


15

Display the Dynamic Link Aggregation

Summary

LAGs can be:

Static (manually configured), which do not use LACP

Dynamic, using LACP

LAG port members can be tagged ports, untagged ports, or dual mode ports

LAGs configured on chassis based systems can span port cards

A primary port must be configured

Primary port configuration is applied to all other members within the LAG


16

E. Multi-chassis Trunking

MCT is a technology that allows two MCT supporting switches to cluster together and appear as

a single logical device. Trunking is a technology that allows multiple links of a device to appear

as one logical link.

The combination of MCT and trunking allows for creating a resilient network topology that

utilizes all links in the network, creating an ideal network topology for latency sensitive

applications.

MCT terminology

MCT cluster: A pair of devices (switches) that is clustered together using MCT to appear as a

single logical device. The devices are connected as peers through an Inter-Chassis Link (ICL).

MCT cluster device: One of the two devices in an MCT cluster.

MCT peer device: From the perspective of an MCT cluster device, the other device in the MCT

cluster.

MCT cluster client: A device that connects with MCT cluster devices through static or dynamic

trunks. It can be a switch or an endpoint server host in the single-level MCT topology or another

pair of MCT devices in a multi-tier MCT topology.

Inter-Chassis Link (ICL): A single-port or multi-port 1 GbE or 10 GbE interface between the two

MCT cluster devices. It provides the control path for CCP for the cluster and also serves as the

data path between the two devices.

MCT VLANs: VLANs on which MCT cluster clients are operating. Any VLAN that has an ICL port is

an MCT VLAN, even though it does not have any clients.

MCT session VLANs: The VLAN used by the MCT cluster for control operations. CCP protocol

runs over this VLAN. The interface can be a single link or a trunk group port. If it is a trunk group

port, it should be the primary port of the trunk group. The MCT session VLAN subnet is not

distributed in routing protocols using redistribute commands.

MCT keep-alive VLAN: The VLAN that provides a backup control path in the event that ICL goes

down.

Cluster Communication Protocol (CCP): A Brocade proprietary protocol that provides reliable,

point-to-point transport to synchronize information between MCT cluster devices. It is the

default MCT control path between the two peer devices. CCP comprises two main components:

CCP peer management and CCP client management. CCP peer management deals with

establishing, and maintaining a TCP transport session between peers, while CCP client

management provides event-based, reliable packet transport to CCP peers.

Cluster Client Edge Port (CCEP): A physical port or trunk group interface on an MCT cluster

device that is connected to client devices.

Cluster Edge Port (CEP): A port on an MCT cluster device that belongs to the MCT VLAN and

connects to an upstream core switch/router, but is neither a CCEP not an ICL.


17

RBridgeID: RBridgeID is a value assigned to MCT cluster devices and clients to uniquely identify

them, and helps in associating the source MAC address with an MCT device.

How MCT works

The MCT initiates at a single MCT-unaware server or switch and terminates at two MCT-aware

devices.

Configuring MCT

This section provides basic configuration steps, which should be completed in the specified

order.

Step 1: Configure LAG.

Step 2: Configure the session VLAN and recommended keep-alive VLAN

Step 3: Configure the cluster

Step 4: Configure clients

After completing these steps, you can verify the configuration by running the show cluster

command

Step 1: Configure LAG

ICL LAG only supports static trunks.

To configure a static LAG, enter the following commands.

Brocade-1 (config)# lag MCT_lag1 static id 2


18

Brocade-1(config-lag-MCT_lag1)# ports ethernet 1/17 to 1/18

Brocade-1(config-lag-MCT_lag1)# primary-port 1/17

Brocade-1(config-lag-MCT_lag1)# deploy

Step 2: Configure the session VLAN and keep-alive VLAN

Enter the following commands.

device-1(config)# vlan 3001 name MCT-keep-alive

device-1(config-vlan-3001)# tagged ethernet 1/9

device-1(config-vlan-3001)# exit

device-1(config)# vlan 3000 name Session-VLAN

device-1(config-vlan-3000)# tagged ether 1/7 to 1/8

device-1(config-vlan-3000)# no spanning-tree

For routers, add the following commands. device-1(config-vlan-3000)# router-interface ve 3000

device-1(config)# interface ve 3000

device-1(config-vif-3000)# ip address 10.1.1.3/24

Step 3: Configure the cluster

Configuration of the peer device involves the peer's IP address, RBridgeID, and ICL

specification. The cluster-id variable must be the same on both cluster devices.

The RBridgeID must be different from the cluster RBridge and any other client in the cluster.

device-1(config)#cluster SX 4000

device-1(config-cluster-SX)#rbridge-id 3

device-1(config-cluster-SX)#session-vlan 3000

device-1(config-cluster-SX)#keep-alive-vlan 3001

device-1(config-cluster-SX)#icl SX-MCT ethernet 1/7

device-1(config-cluster-SX)#peer 10.1.1.2 rbridge-id 2 icl SX-MCT

device-1(config-cluster-SX)#deploy

Step 4: Configure clients

Client configuration requires the client name, RBridgeID, and CCEP.

The client RBridgeID must be identical on both of the cluster devices.

device-1(config-cluster-SX)# client client-2

device-1(config-cluster-SX-client-1)#rbridge-id 200

device-1(config-cluster-SX-client-1)#client-interface ether 1/5

device-1(config-cluster-SX-client-1)#deploy


19

Displaying MCT information

Use the show cluster config command to display the peer device and client states.

device#show cluster SXR122 config

cluster SXR122 100

rbridge-id 100

session-vlan 1

keep-alive-vlan 3

icl SXR122-MCT ethernet 1/1

peer 172.17.0.2 rbridge-id 101 icl SXR122-MCT

deploy

client KL134

rbridge-id 14

client-interface ethernet 1/23

deploy

device#show cluster 1 client

Cluster 1 1

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

Rbridge Id: 101, Session Vlan: 3999, Keep-Alive Vlan: 4001

Cluster State: Deploy

Client Isolation Mode: Loose

Configured Member Vlan Range: 100 to 105

Active Member Vlan Range: 100 to 105

MCT Peer's Reachability status using Keep-Alive Vlan: Peer Reachable

Client Info:

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

Client: c1, rbridge-id: 300, Deployed

Client Port: 3/11

State: Up

Number of times Local CCEP down: 0

Number of times Remote CCEP down: 0

Number of times Remote Client undeployed: 0

Total CCRR packets sent: 4

Total CCRR packets received: 3

Some show commands for MCT troubleshooting

device#show cluster 1 ccp peer

device#show interface ethernet 7/1

device#show span


20

F. Virtual Router Redundancy Protocol Enhanced

VRRP-e is Brocades enhanced version of VRRP that overcomes limitations in the standard

protocol

All routers start as backup

The router with the highest priority becomes the master

If there is a tie for highest priority, the router with the highest interface IP

address becomes master

The VIP is a unique IP address on the same subnet as the VRRP-e routers

There is no concept of an owner IP address, as a real interface IP is not used

The elected master hosts the VIP address and answers ICMP requests

VRRP-e uses UDP (port 8888) to send multicast hello messages to the "all routers"

multicast address 224.0.0.2

VRRP-e Master Selection

All VRRP-E routers start as a backup and send hello messages to determine the master router

Router with highest VRRP-E priority becomes master

Master sends hellos as a keep-alive and responds to ARP and ICMP requests (i.e. ping)


21

Example of Multiple VRRP-e Virtual Routers

Configuring VRRP-e

To configure the first VRRP-e virtual router from the example on the privies slide1:

Router_A(config)# router vrrp-extended

Router_A(config-VRRP-e-router)# interface ethernet 1

Router_A(config-if-e100-1)# ip address 192.53.5.2/24

Router_A(config-if-e100-1)# ip vrrp-extended vrid 1

Router_A(config-if-e100-1-vrid-1)# backup priority 110 track-priority 20

Router_A(config-if-e100-1-vrid-1)# ip-address 192.53.5.1


22

Router_A(config-if-e100-1-vrid-1)# track-port ethernet 16

Router_A(config-if-e100-1-vrid-1)# activate

VRRP-e router 1 for this interface is activating

Verify VRRP-e Configuration Master

Router_A(config)# show ip vrrp-e

Total number of VRRP-Extended routers defined: 2

Interface ethernet 1

auth-type no authentication

VRID 1

state master

administrative-status enabled

Virtual MAC 02e0.5279.a401

priority 110

current priority 110

track-priority 20

hello-interval 1 sec

dead-interval 0 sec

current dead-interval 3.500 sec

preempt-mode true

virtual ip address 192.53.5.1

advertise backup: disabled

next hello sent in 00:00:00

track-port 16(up)

Verify VRRP-e Configuration Backup

Router_B(config)# show ip vrrp-e




VRID 1

state backup



priority 100


track-priority 20


dead-interval 0 sec


23


preempt-mode true



master router 192.53.5.2 expires in 00:00:03

track-port 12(up)

Troubleshooting VRRP-e





VRID 1

state initialize



priority 110


track-priority 20


dead-interval 0 sec


preempt-mode true



track-port 16(up)





VRID 1

state backup



priority 110

current priority 90

track-priority 20


dead-interval 0 sec


24


preempt-mode true



master router 192.53.5.3 expires in 00:00:03

track-port 16(down)

Optional VRRP-e Configuration

Non-preempt-mode

The non-preempt-mode prevents a VRRP-e router with a higher priority than a currently healthy

master from automatically taking ownership of the VRID

Preempt-mode is enabled by default allowing failback to a reinstated master to occur

automatically

Configured on each VRID

Router_A(config-if-e100-1-vrid-1)# non-preempt-mode

Slow start

By default, after a failover, if the master becomes available again it takes over as master

immediately

Slow Start timer causes a configured amount of time to elapse before the master is restored

This interval allows time for OSPF convergence when the master is restored

Single setting for all VRIDs entered in seconds

FastIron switches

FES(config)# router vrrp-e

FES(config-VRRP-e-router)# slow-start 30

Non FastIron switches

Non-FES(config)# vrrp-e slow-start 30

Summary

VRRP and VRRP-e provide redundancy to default gateways servicing hosts on the same subnet

Allows an alternate router path for a host without changing the IP address or MAC

address of its gateway

Reliability is achieved by advertising a virtual router as the default gateway

VRRP-e is Brocades enhanced version of VRRP that overcomes limitations in the

standard protocol

VIP can be any unused IP address within the same subnet

Can ping VIP regardless of who is master


25

2014 Brocade Communications Systems, Inc. All Rights Reserved.

ADX, AnyIO, Brocade, Brocade Assurance, the B-wing symbol, DCX, Fabric OS, ICX, MLX, MyBrocade, OpenScript, VCS, VDX, and Vyatta are

registered trademarks, and HyperEdge, The Effortless Network, and The On-Demand Data Center are trademarks of Brocade

Communications Systems, Inc., in the United States and/or in other countries. Other brands, products, or service names mentioned may

be trademarks of their respective owners.

Notice: This document is for informational purposes only and does not set forth any warranty, expressed or implied, concerning any

equipment, equipment feature, or service offered or to be offered by Brocade. Brocade reserves the right to make changes to this

document at any time, without notice, and assumes no responsibility for its use. This informational document describes features that may

not be currently available. Contact a Brocade sales office for information on feature and product availability. Export of technical data

contained in this document may require an export license from the United States government.

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L2 and L3 Functions

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