How many route to one destination can be supported in Cisco 3560 G switch?

wang3-114 · ‎11-14-2008

I want to know how many routes which are to same destination but with different next hop can be supported in Cisco 3560G Switch.And can traffic be balanced among these routes?

Joseph W. Doherty · ‎11-14-2008

Unsure whether 3560G, when routing, different from most other Cisco routers, but most others usually default to supporting 4 equal cost paths if the routing protocol supports (e.g. OSPF, EIGRP) and just one path for BGP. Most also support increasing multiple paths to 6, although believe some Cisco devices now allow more than 6. EIGRP can also support multiple unequal cost paths, if configured to do so, and believe if it is, it too starts with up to 4 unless config increases value.

wang3-114 · ‎11-14-2008

Thanks for your response!

I configured 2 static route to one destination with same subnet mask but different next-hop.I oberverd that all traffic is through one route.

ip route 172.27.10.49 255.255.255.255 172.27.10.9

ip route 172.27.10.49 255.255.255.255 172.27.10.13

Joseph W. Doherty · ‎11-14-2008

CEF active?

Multiple concurrent sending source hosts or flows to same host destination? (Same flow, by default, would take just one path.)

wang3-114 · ‎11-17-2008

Thanks for your help very much!

It is from one source to one destination but through many equal static route(many different next-hop).My understanding is that in such situation flow can not be balanced in many static equal routes. Is it right?And if there anyway to balance the flow among routes?

Joseph W. Doherty · ‎11-17-2008

If the device supports CEF packet-by-packet, a single flow should be split across multiple paths. However, this can result in packets arriving out of sequence which many protocols don't like, although packet sequencing isn't guaranteed by IP.

Mohamed Sobair · ‎11-17-2008

Hi,

Adding to Joseph's:

In order to perform equal cost load-sharing, both routes should have the Same of the following:

1- Prefix length. (Subnetmask of the route).

2- Administrative Distance.

3- Cost of both routes.

HTH

Mohamed