[c-nsp] Adding a second switch for redundancy

[Eric Kagan]

> Eric Kagan wrote:
> > I am trying to lab the following - Several routers plugged 
> in to two 
> > seperate switches for redundancy.  Catalyst 3524XL/3550.  7200/7500 
> > routers
> > - 
> > 
> > 
> > Design A (works fine - diagram below)
> > 
> > 5 routers plugged in to a 3550 (configured as Layer 2 
> ports).  We are 
> > running EIGRP on the routers.
> > 
> > 
> > 
> > Design B (EIGRP Errors - diagram below)
> > 
> > We added 2nd FE cards to the routers
> > We plugged them in to the new switch
> > We assigned a new / separate subnet for the interfaces.
> > 
> > When we bring them up, we get EIGRP flaps. (log clip below) 
> Are there 
> > EIGRP settings that need to be changed for having 2 FE's 
> from the same 
> > routers in different switches ?  Do the switches need to be 
> trunked ?
> > 
> > Thanks
> > Eric
> > 
> > 
> > 
> > Design A: (working - single switch, multiple routers)
> > 
> > 
> > -----------------
> > |  Cat 3550-A   |
> > -----------------
> >   |   |   |   | ----- 1.1.1.0 /24 (EIGRP)
> >   R   R   R   R
> > 
> > 
> > Design B: (problem)
> > 
> > 
> > -----------------
> > |  Cat 3550-A   |
> > -----------------
> >   |   |   |   | ----- 1.1.1.0 /24 (EIGRP)
> >   R   R   R   R
> >   |   |   |   | ----- 2.1.1.0 /24 (EIGRP)
> > -----------------
> > |  Cat 3550-B   |
> > -----------------
> > 
> 
> Well, assuming that 3550-A and 3550-B are not connected in 
> any way, I wouldn't think there would be any problem.

The 2 switches are not directly connected in any way.  They are completely
separate from each other.
 
> Is there more info here than is implied in simple ASCII art?  

Not really - its pretty simple.  The routers do have HSRP and MPLS running
since I am using our actual production configs on the lab routers.

> Config snippet would be helpful...

Clips from 2 routers and both switches for those router - 

Thanks
Eric

R1 - (BGP Border router)

interface FastEthernet0/0
 ip address 2.1.1.12 255.255.255.0
 no ip unreachables
 ip flow ingress
 load-interval 30
 duplex full
 no clns route-cache
!
interface GigabitEthernet4/0
 ip address 1.1.1.1.12 255.255.255.0
 no ip redirects
 negotiation auto
 no clns route-cache
 standby 2 ip 1.1.1.1
 standby 2 priority 105
 standby 2 preempt
!
router eigrp 65555
 redistribute connected
 redistribute static metric 10000 100 255 1 1500
 network 1.1.1.0 0.0.0.255
 network 2.1.1.0 0.0.0.255
 no auto-summary


R2 - (PE/VPN Agg)

interface FastEthernet0/0
 ip address 1.1.1.10 255.255.255.0
 no ip unreachables
 ip flow ingress
 load-interval 30
 duplex full
 tag-switching mtu 1524
 tag-switching ip
 no clns route-cache
 standby 2 ip 1.1.1.1
 standby 2 preempt
!
interface FastEthernet6/0
 ip address 2.1.1.10 255.255.255.0
 ip flow ingress
 duplex full
 mpls label protocol ldp
 tag-switching mtu 1524
 tag-switching ip
 no clns route-cache
!
router eigrp 65555
 redistribute connected
 redistribute static
 network 1.1.1.0 0.0.0.255
 network 2.1.1.0 0.0.0.255
 no auto-summary


Sw1 - 

interface FastEthernet0/13
 description connected to R2
 switchport mode dynamic desirable
 no ip address
 duplex full
 speed 100
!
interface GigabitEthernet0/1
 description connected to R1 PA-GE (G4/0)
 switchport mode dynamic desirable
 no ip address
!
interface Vlan1
 ip address 1.1.1.4 255.255.255.0
!
router eigrp 65555
 network 1.1.1.0 0.0.0.255
 network 2.1.1.0 0.0.0.255
 no auto-summary
 eigrp log-neighbor-changes


sw2 - 

!
interface FastEthernet0/1
 description connected to R1 (F0/0)
 duplex full
 switchport access vlan 2
!
interface FastEthernet0/5
 description connected to R2-f6/0
 mtu 1548
 duplex full
 switchport access vlan 2
!
interface VLAN1
 no ip address
 no ip directed-broadcast
 no ip route-cache
 shutdown
!
interface VLAN2
 ip address 2.1.1.4 255.255.255.0
 no ip directed-broadcast
 no ip route-cache