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Cisco Catalyst Switch Module 3110 and 3012 for IBM BladeCenter Software Configuration Guide
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Chapter 38 Configuring IP Unicast Routing
Configuring Stub Routing
Switch(config-if)# no switchport
Switch(config-if)# ip address 10.1.1.1 255.255.255.0
Switch(config-if)# ip pim passive
Switch(config-if)# end
To verify that PIM stub is enabled, use the show ip pim interface privileged EXEC command:
Switch# show ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
3.1.1.2 GigabitEthernet1/0/25 v2/SD 1 30 1 3.1.1.2
100.1.1.1 Vlan100 v2/P 0 30 1 100.1.1.1
10.1.1.1 GigabitEthernet1/0/20 v2/P 0 30 1 10.1.1.1
Use these privileged EXEC commands to display information about PIM stub configuration and status:
• show ip pim interface displays the PIM stub information.
• show ip igmp detail displays the interested clients that have joined the specific multicast source
group.
• show ip igmp mroute verifies that the multicast stream forwards from the source to the interested
clients.
Understanding EIGRP Stub Routing
In a network using EIGRP stub routing, the only allowable route for IP traffic to the user is through a
switch that is configured with EIGRP stub routing. The switch sends the routed traffic to interfaces that
are configured as user interfaces or are connected to other devices.
Note The IP base feature set contains EIGRP stub routing capability, which only advertises connected or
summary routes from the routing tables to other switches in the network. The switch uses EIGRP stub
routing at the access layer to eliminate the need for other types of routing advertisements. For enhanced
capability and complete EIGRP routing, the switch must be running the IP services feature set.
On a switch running the IP base feature set, if you try to configure multi-VRF-CE and EIGRP stub
routing at the same time, the configuration is not allowed.
When using EIGRP stub routing, you need to configure the distribution and remote routers to use EIGRP
and to configure only the switch as a stub. Only specified routes are propagated from the switch. The
switch responds to all queries for summaries, connected routes, and routing updates.
Any neighbor that receives a packet informing it of the stub status does not query the stub router for any
routes, and a router that has a stub peer does not query that peer. The stub router depends on the
distribution router to send the proper updates to all peers.
In Figure 38-5, Switch B is configured as an EIGRP stub router. Switches A and C are connected to the
rest of the WAN. Switch B advertises connected, static, redistribution, and summary routes to
Switches A and C. Switch B does not advertise any routes learned from Switch A (and the reverse).
