Cisco Catalyst 4500 Series Administration Guide

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Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
OL_28731-01
Chapter 34 Configuring Layer 3 Interfaces
Configuring EIGRP Stub Routing
Figure 34-3 EIGRP Stub Switch Configuration
For more information about EIGRP stub routing, see the “Configuring EIGRP Stub Routing” part of the
Cisco IOS IP Configuration Guide, Volume 2 of 3: Routing Protocols, Release 12.2.
Configuring EIGRP Stub Routing
The EIGRP stub routing feature improves network stability, reduces resource utilization, and simplifies
stub switch configuration.
Stub routing is commonly used in a hub-and-spoke network topology. In a hub-and-spoke network, one
or more end (stub) networks are connected to a remote switch (the spoke) that is connected to one or
more distribution switches (the hub). The remote switch is adjacent only to one or more distribution
switches. The only route for IP traffic to follow into the remote switch is through a distribution switch.
This type of configuration is commonly used in WAN topologies where the distribution switch is directly
connected to a WAN. The distribution switch can be connected to many more remote switches. Often,
the distribution switch is connected to 100 or more remote routers. In a hub-and-spoke topology, the
remote router must forward all nonlocal traffic to a distribution router, so it becomes unnecessary for the
remote router to hold a complete routing table. Generally, the distribution router need not send anything
more than a default route to the remote router.
When using the EIGRP stub routing feature, you need to configure the distribution and remote routers
to use EIGRP, and to configure only the remote router as a stub. Only specified routes are propagated
from the remote (stub) router. The stub router responds to all queries for summaries, connected routes,
redistributed static routes, external routes, and internal routes with the message “inaccessible.” A router
that is configured as a stub sends a special peer information packet to all neighboring routers to report
its status as a stub router.
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.
Figure 34-4 shows a simple hub-and-spoke configuration.
Host A Host B
Switch B
Switch A
Routed to WAN
Switch C
Host C
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Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E