How to aggregate links on multiple devices

jquintard · ‎10-14-2011

Hello,

Hello this the night, probably simple but I dont find how to do it...

My topology is this like this :

      /----- Switch 1 --- R1 --- ISP1
      |            |                 |
Server       |                 |
      |            |                 |
      \----- Switch 2 --- R2 --- ISP2

- Switch 1 and Switch 2 are linked for redundancy

- R1 and R2 are connected (fa2/0) for iBGP and HSRP

R1 (connected to ISP1 and R2)

interface FastEthernet1/0

ip address 10.10.40.1 255.255.255.0

standby 1 ip 10.10.40.10

standby 1 preempt delay minimum 60

standby 1 track FastEthernet2/0

interface FastEthernet2/0

ip address 10.10.30.1 255.255.255.248

R2 (connected to ISP2 and R1)

interface FastEthernet1/0

ip address 10.10.40.2 255.255.255.0

standby 1 ip 10.10.40.10

standby 1 priority 10

standby 1 preempt

interface FastEthernet2/0

ip address 10.10.30.2 255.255.255.248

Server (emulated with a cisco router) :

interface FastEthernet0/0

ip address 10.10.40.100 255.255.255.0

interface FastEthernet1/0

no ip add

shut

ip route 0.0.0.0 0.0.0.0 10.10.40.10

Just one question :

- It's impossible to set different IP address is the same subnet to Fa0/0 and Fa1/0. So how to configure this router to use 10.10.40.10 as default route with one link on each switch/router... Like an aggregation but with multiple device... Two L2 interfaces and an L3 aggregation ?

Linux and windows have an arp/ip bonding feature...

Thanks

Jerome

Jon Marshall · ‎10-15-2011

Jerome

Not entirely sure what you are asking.

When you say So how to configure this router to use 10.10.40.10 as default route with one link on each switch/router...

are you talking about the router acting as a host. If so there are a couple of things here -

1) a router is not a server. On a server you could run the NICs in an etherchannel and connect them to the switches. However this supposes -

2) that your switches are capable of having an etherchannel from the "server" to be spread across both switches. This is not possible on normal switches ie. all the etherchannel ports must be terminated on the same physical chassis. But if your switches are 3750s/6500s/Nexus then you can spread the etherchannel across the 2 switch chassis's.

So if this was a server running etherchannel and the switches were one of the above you could use both NICs to forward traffic to the switches.

3) then there is the router connection. In the current setup once the packets gets to the switch(es) it will still be forwarded to the active HSRP gateway so it will always go to the one router. With HSRP you can't really get around that.

You could run GLBP on the routers which would load-balance the traffic but that it still done a per host basis so once the "server" has been allocated one of the routers as it's forwarding device with GLBP it will stick with that one so again that doesn't solve your problem.

If you want to use all links then a better approach is -

1) connect server to a pair of 3750/6500/Nexus switches.

2) have the switches do inter-vlan routing

3) connect the switches to the routers using L3 P2P links.

4) Use a dynamic routing protocol between the switches and the routers.

Jon

jquintard · ‎10-16-2011

Jon,

In fact it's a GNS Lab. I try to do a port channel with a esw16 in the router emulated the pc but this module can't use this feature. I going to replace this host with a real Linux OS emulated with qemu. I can't use gblp because my ISP bandwidth are not different so hsrp is the best solution.

2 switchs + stp and an host with 2 nic + ip bonding, it's a correct redundancy solution for you or do you have another solution ?

Jerome