Layer 2/3 Switching Software Configuration Guide for Cisco 1000 Series Connected Grid Routers (Cisco IOS)

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Updated:March 6, 2014

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Table of Contents

Layer 2/3 Switching Software Configuration Guide for Cisco 1000 Series Connected Grid Routers (Cisco IOS)

Information About Ethernet Switches

Port Configuration

IGMP Version 3

Switch Port Numbering and Naming

Fast Ethernet Switching Supported SNMP MIBs

BRIDGE-MIB for Layer 2 Ethernet Switching

Prerequisites

Guidelines and Limitations

Configuring Fast Ethernet Switches

Configuring VLANs

Configuring VLANs on the Fast Ethernet Ports

Configuring VLANs on the Gigabit Ethernet Ports

Configuring a Fast Ethernet as Routed (Layer 3) Interface

Configuring a Gigabit Ethernet as Routed (Layer 3) Interface

Configuration Example

Sample SVI Example

Sample Output for the show vlan-switch Command

Related Documentation

Layer 2/3 Switching Software Configuration Guide for Cisco 1000 Series Connected Grid Routers (Cisco IOS)

First Published: December 2013

Release: Cisco IOS Release 15.4(1)CG

OL-31394-01

This docment gives an overview of configuration tasks for the Ethernet switching feature set on the Cisco 1120 and 1240 Connected Grid Routers (hereafter referred to as CGR 1000), running CG IOS release 15.4(1)CG. This document contains the following sections:

Information About Ethernet Switches

Port Configuration

The Cisco CGR 1120 has 8 Ethernet ports: 6 FE ports, and 2 GE switch ports. The Cisco CGR 1240 has 6 Ethernet ports: 4 FE ports and 2 GE switch ports. On both of the CGRs, you can configure the 2 GE ports to operate in Layer 2 mode or the default Layer 3 mode. You can convert the switch to Layer 2 mode by using the switchport command.

Note Layer 2 switching is hardware switched. Layer 3 switching is software forwarding.

  • The FE ports are 100BaseT Layer 2. Traffic between different VLANs on a switch is routed through the router platform using the switched virtual interface (SVI). You can configure FE switch ports as Layer 3 (routed) ports by configuring the no switchport command on interface fastethernet x/y . By default, FE switch ports are Layer 2.
  • The GE ports are 1000BaseT Layer 2. Traffic between different VLANs on a switch is routed through the router platform using the switched virtual interface (SVI). You can configure GE switch ports as Layer 2 ports by configuring the switchport command on interface gigabit ethernet x/y . By default, GE ports are Layer 3 (routed ports).

Any switch port can be configured as a trunking port to connect to other Cisco Ethernet switches.

IGMP Version 3

Cisco 1120 and 1240 CGRs support IGMP Version 3 (IGMPv3) snooping. IGMPv3 provides support for source filtering, which enables a multicast receiver host to signal to a router which groups the receiver host wants to receive multicast traffic from and from which sources this traffic is expected. Enabling the IGMPv3 feature with IGMP snooping on Cisco CGRs provides Basic IGMPv3 Snooping Support. This provides constrained flooding of multicast traffic in the presence of IGMPv3 hosts and constrains traffic to approximately the same set of ports as IGMPv2 snooping does with IGMPv2 hosts. Constrained flooding only considers the destination multicast address.

Switch Port Numbering and Naming

The ports on the FE switch are numbered FE2/3–FE2/8 on CGR1120 routers; FE2/3–FE2/6 on CGR1240 routers. The ports on the GE switch are labeled GE ports are GI2/1–GI2/2.

Fast Ethernet Switching Supported SNMP MIBs

Simple Management Network Protocol (SNMP) development and use is centered around the Management Information Base (MIB). See Overview of SNMP MIBs for more information.

BRIDGE-MIB for Layer 2 Ethernet Switching

The Layer 2 Ethernet Switching Interface BRIDGE-MIB is supported in the Cisco 1120 and 1240 platforms. The BRIDGE-MIB allows you to determine the Media Access Control (MAC) addresses and spanning tree information of the Ethernet switch modules. You can query the MIB agent using the SNMP protocol, and view the details of Ethernet switch modules such as the MAC address of each interface and spanning protocol information.

The Bridge-MIB uses the following approaches to get the L2 layers BRIDGE-MIB information:

• Community-string-based approach

  • Context-based approach

In the community-string-based approach, one community string is created for each VLAN. Based on the query, the respective VLAN MIB displays.

To get the BRIDGE-MIB details, use the snmp-server community public RW command in configuration mode:

router(config)#snmp-server community public RW
 

Use the following syntax to query the SNMP BRIDGE-MIB details:

snmpwalk -v2c <ip address of the CGR, …> public .1.3.6.1.2.1.17
snmpwalk -v2c <ip address of the CGR, …> public@2 .1.3.6.1.2.1.17
snmpwalk -v2c <ip address of the CGR, …> public@3 .1.3.6.1.2.1.17

Note When you create a VLAN “x”, the logical entity public@x is added. If you query with the public community, the L3 MIB displays. When you query with public@x, the L2 MIB for VLAN “x” displays.

In the context-based approach, use the SNMP context mapping commands to display the values for L2 interfaces. Each VLAN is mapped to a context. When you query with a context, the MIB displays the data for the specified VLAN, which is then mapped to the context. In this approach, each VLAN is manually mapped to a context.

To get the BRIDGE-MIB details, use the following commands in configuration mode:

router(config)#routersnmp-server group public v2c context bridge-group
router(config)#snmp-server community public RW
router(config)#snmp-server community private RW
router(config)#snmp-server context bridge-group
router(config)#snmp mib community-map public context bridge-group
 

Use the following syntax to query the SNMP BRIDGE-MIB details:

snmpwalk -v2c <ip address of the CGR, …> public@1 .1.3.6.1.2.1.17 ?L2-MIB
snmpwalk -v2c <ip address of the CGR, …> private .1.3.6.1.2.1.17?L3-MIB
 

Note When you query with the public community, the L2 MIB displays.
Use the private group for L3 MIB.

Prerequisites

To configure Ethernet switches, you must understand the following concepts:

• VLANs and VLAN Trunk Protocol

• Layer 2 Ethernet Switching

• 802.1x Authentication

Guidelines and Limitations

The following restrictions apply to the FE switch:

  • The ports of an FE switch must NOT be connected to any onboard Fast Ethernet port.
  • Inline power is not supported.
  • VTP pruning is not supported.
  • FE switches support up to 200 secure MAC addresses.

Configuring Fast Ethernet Switches

The following sections present configuration tasks for the CGR 1000:

• Configuring VLANs

• Configuring a Fast Ethernet as Routed (Layer 3) Interface

• Configuring a Gigabit Ethernet as Routed (Layer 3) Interface

The following links present configuration tasks for these features in the CGR 1000:

• Configuring Layer 2 Interfaces

• Configuring IEEE 802.1x Port-Based Authentication

• Configuring Spanning Tree Protocol

• Configuring MAC Address Notification Traps

• Configuring the MAC Table to Provide Port Security

• Verifying Cisco Discovery Protocol

• Configuring Switched Port Analyzer (SPAN)

• Enabling and Verifying IP Multicast Layer 3 Switching

• The BRIDGE-MIB

• Configuring IGMP Snooping

• Configuring Fallback Bridging

Configuring VLANs

This section provides information on how to configure VLANs on the CGR 1000, which support 64 VLANs.

Configuring VLANs on the Fast Ethernet Ports

BEFORE YOU BEGIN

DETAILED STEPS

 

Comand
Purpose

Step 1

interface fe port

Selects the FE port to configure.

Step 2

shutdown

(Optional) Shuts down the interface to prevent traffic flow until configuration is complete.

Step 3

switchport access vlan vlan_id

Creates instances of additional VLANs. Valid values for vlan_id are 2 to 4094.

Note The values 1002 to 1005 are reserved.

Step 4

no shutdown

Activates the interface.

Step 5

end

Exits configuration mode.

Step 6

show vlan-switch [brief | id vlan | name name]

(Optional) Displays VLAN information.

  • The optional brief keyword displays only a single line for each VLAN, naming the VLAN, status, and ports.
  • The optional id keyword displays information about a single VLAN identified by VLAN ID number; valid values are from 1 to 4094.
Note The values 1002 to 1005 are reserved.

  • The optional name keyword displays information about a single VLAN identified by VLAN name; valid values are an ASCII string from 1 to 32 characters.

EXAMPLE

This example shows how to define an access VLAN on Fast Ethernet port 2:

router# configure terminal
router(config-if)# interface fa 2/1
router(config-if)# shutdown
router(config-if)# switchport access vlan 32
router(config-if)# no shutdown
router(config-if)# exit
router# show vlan-switch name vlan0032

Configuring VLANs on the Gigabit Ethernet Ports

BEFORE YOU BEGIN

DETAILED STEPS

 

Comand
Purpose

Step 1

interface ge port

Selects the GE port to configure.

Step 2

shutdown

(Optional) Shuts down the interface to prevent traffic flow until configuration is complete.

Step 3

switchport

Configures the GE port for Layer 2 switching.

Note You must enter the switchport command once without any keywords to configure the Fast Ethernet port as a Layer 2 port before you can enter additional switchport commands with keywords. This command creats a Cisco default VLAN.

This configuration sets the default trunking administrative mode to switchport mode dynamic desirable and the trunk encapsulation to negotiate .

By default, all VLANs created are included in the default trunk.

Step 4

switchport access vlan vlan_id

Creates instances of additional VLANs. Valid values for vlan_id are 2 to 4094.

Note The values 1002 to 1005 are reserved.

Step 5

no shutdown

Activates the interface.

Step 6

end

Exits configuration mode.

Step 7

show vlan-switch [brief | id vlan | name name]

(Optional) Displays VLAN information.

  • The optional brief keyword displays only a single line for each VLAN, naming the VLAN, status, and ports.
  • The optional id keyword displays information about a single VLAN identified by VLAN ID number; valid values are from 1 to 4094.
Note The values 1002 to 1005 are reserved.

  • The optional name keyword displays information about a single VLAN identified by VLAN name; valid values are an ASCII string from 1 to 32 characters.

EXAMPLE

This example shows how to define an access VLAN, VLAN 27, on Gigabit Ethernet port 2:

router# configure terminal
router(config-if)# interface ge 2/1
router(config-if)# switchport
router(config-if)# switchport access vlan 27
router(config-if)# no shutdown
router(config-if)# exit
router# show vlan-switch name vlan0027

Configuring a Fast Ethernet as Routed (Layer 3) Interface

BEFORE YOU BEGIN

DETAILED STEPS

 

Comand
Purpose

Step 1

interface type number

Enters the configuration mode for a Fast Ethernet interface on the router.

Step 2

no switchport

Enables Layer 3 functionality (routed port) on Fast Ethernet interfaces.

Step 3

ip address ip-address mask

Sets the IP address and subnet mask for the specified Fast Ethernet interface.

Step 4

no shutdown

Activates the FE interface, changing its state from administratively down to administratively up.

Step 5

exit

Exits configuration mode for the Fast Ethernet interface and returns to global configuration mode.

EXAMPLE

This example shows how to enable Layer 3 functionality on Fast Ethernet port 2/3:

router# configure terminal
router(config)# interface fastethernet 2/3
router(config)# no switchport
router(config-if)# ip address 192.168.12.2
255.255.255.0
router(config-if)# no shutdown
router(config-if)# exit

Configuring a Gigabit Ethernet as Routed (Layer 3) Interface

BEFORE YOU BEGIN

DETAILED STEPS

 

Comand
Purpose

Step 1

interface type number

Enters the configuration mode for a Gigabit Ethernet WAN interface on the router.

Step 2

ip address ip-address mask

Sets the IP address and subnet mask for the specified Gigabit Ethernet interface.

Step 3

no shutdown

Activates the GE interface, changing its state from administratively down to administratively up.

Step 4

exit

Exits configuration mode for the Gigabit Ethernet interface and returns to global configuration mode.

EXAMPLE

This example shows how to enable Layer 3 functionality on Gigabit Ethernet port 2/1:

router# configure terminal
router(config)# interface gigabitethernet 2/1
router(config-if)# ip address 192.168.12.2
255.255.255.0
router(config-if)# no shutdown
router(config-if)# exit

Configuration Example

This example configures VLANs on the Fast Ethernet and Gigabit Ethernet ports, and configures Fast Ethernet ports 2/3, Gigabit Ethernet ports 2/1:

router# configure terminal
router(config-if)# interface Fa 2/4
router(config-if)# shutdown
router(config-if)# switchport access vlan 32
router(config-if)# no shutdown
router(config-if)# exit
router#
router(config)# interface fastethernet 2/3
router(config)# no switch port
router(config-if)# ip address 192.168.12.2 255.255.255.0
router(config-if)# no shutdown
router(config-if)# exit
router(config-if)# interface Gi 2/2
router(config-if)# switch port
router(config-if)# switchport access vlan 27
router(config-if)# no shutdown
router(config-if)# exit
router#
router(config)# interface gigabitethernet 2/1
router(config-if)# ip address 192.168.12.2 255.255.255.0
router(config-if)# no shutdown
router(config-if)# exit

Sample SVI Example

This example shows how SVI provides L3 routing capabilities for the switch ports:

router# configure terminal
router(config)# interface vlan 10
router(config-if)# ip address 10.1.1.1 255.255.255.0
router(config-if)# no shutdown
router(config-if)# exit
 

Sample Output for the show vlan-switch Command

The following example displays the output that verifies VLAN configuration:

router# show vlan-switch name vlan0032
router#show vlan-s name vlan0032
 
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
32 vlan0032 active Fa2/4
 
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
32 enet 100032 1500 - - - - - 0 0
 
router# show vlan-switch name vlan0027
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
32 vlan0032 active Gi2/2
 
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
32 enet 100032 1500 - - - - - 0 0
 

The following example uses the brief keyword to verify that VLAN 2 was deleted:

router# show vlan-switch brief

 

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/2, Fa0/9, Fa0/14, Gi0/0
3 VLAN0003 active Fa0/4, Fa0/5, Fa0/10, Fa0/11
4 VLAN0004 active Fa0/6, Fa0/7, Fa0/12, Fa0/13
5 VLAN0005 active
40 VLAN0040 active Fa0/15
50 VLAN0050 active
1000 VLAN1000 active
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active

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