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MCScrapE
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 Load Balancing 2 T1′s with Cisco 2600
Cisco, Networking, Routers
I have a Cisco 2600 with 2 ISPs each terminating on a CSU/DSU WIC. I have pasted below the relevant parts of the config and I need to used sub-interfaces for the fast ethernet for client requirements. I have enabled ip cef and have made the ip routes for each serial interface the same cost. Is that all I have to do? How can I properly tell that traffic is going between the two lines? Thanks. ------------------------------------------------- ip subnet-zero ip cef ip cef accounting per-prefix ip cef load-sharing algorithm universal 00000001 ! ! no ip domain-lookup ip domain-name domain.com ip name-server 1.1.1.1 ! ! no call rsvp-sync ! ! ! ! ! ! ! ! interface FastEthernet0/0 no ip address ip load-sharing per-packet duplex auto speed auto ! interface FastEthernet0/0.256 encapsulation dot1Q 256 ip address x.x.x.x 255.255.255.128 ip load-sharing per-packet no cdp enable ! interface FastEthernet0/0.257 encapsulation dot1Q 257 ip address x.x.x.x 255.255.255.224 no cdp enable ! interface Serial0/0 no ip address ip directed-broadcast encapsulation frame-relay IETF no fair-queue service-module t1 timeslots 1-24 frame-relay lmi-type ansi ! interface Serial0/0.1 point-to-point ip address x.x.x.x 255.255.255.252 frame-relay interface-dlci 500 IETF ! interface Serial0/1 bandwidth 1544 ip address x.x.x.x 255.255.255.252 ! router bgp xxxxx bgp router-id x.x.x.x bgp cluster-id yyyyyyyyy bgp log-neighbor-changes network x.x.x.x. mask 255.255.255.0 neighbor x.x.x.x remote-as neighbor x.x.x.x password neighbor x.x.x.x soft-reconfiguration inbound neighbor x.x.x.x route-map ISP2-in in neighbor x.x.x.x route-map ISP2-out out neighbor x.x.x.x remote-as neighbor x.x.x.x password neighbor x.x.x.x soft-reconfiguration inbound neighbor x.x.x.x route-map ISP1-in in neighbor x.x.x.x route-map ISP2-out out ! ip classless ip route 0.0.0.0 0.0.0.0 Serial0/0.1 31 ip route 0.0.0.0 0.0.0.0 Serial0/1 31 ip route x.x.x.x 255.255.255.0 Null0 no ip http server ! access-list 1 permit any access-list 2 deny any access-list 3 permit x.x.x.x 0.0.0.255 access-list 4 permit 0.0.0.0 access-list 110 permit ip x.x.x.x 0.0.0.7 any access-list 112 permit ip x.x.x.x 0.0.0.255 any no cdp run route-map FastEthernet0/0-policy permit 10 match ip address 110 set ip next-hop x.x.x.x ! route-map FastEthernet0/0-policy permit 12 match ip address 112 set ip next-hop x.x.x.x ! route-map ISP2-out permit 10 match ip address 3 ! route-map ISP1-out permit 10 match ip address 3 ! route-map ISP1-in permit 10 match ip address 4 ! route-map ISP2-in permit 10 match ip address 4

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ASKED: November 8, 2004  10:24 PM
UPDATED: November 9, 2004  7:12 PM
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The 2 static routes going to each of the ISPs with the same cost should be all that is required to load balance. One way to verify this is to shut down one of the serial interfaces and run a ping to a public IP. If the paths were load balancing you'd get a !.!.!.! response becuase the router would be trying to send every other packet out the shutdown path.
Last Wiki Answer Submitted:  November 9, 2004  6:38 pm  by  Jrgreenberg   0 pts.
All Answer Wiki Contributors:  Jrgreenberg   0 pts.
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The 2 static routes going to each of the ISPs with the same cost should be all that is required to load balance. One way to verify this is to shut down one of the serial interfaces and run a ping to a public IP. If the paths were load balancing you’d get a !.!.!.! response becuase the router would be trying to send every other packet out the shutdown path.

Jrgreenberg
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