06-21-2013 09:42 AM
In order to find a outgoing interface for a incoming packet does the router refer below two commands ? First table to get the mapping of IP-MAC and then to find out from which interface the destination MAC address can be reached.
06-21-2013 02:45 PM
You can use "show ip route" command first. You need to know what’s the destination IP address of traffic. For example, destination IP is 100.x.x.y. Then you do:
FCX_STK_2#show ip route 100.x.x.y
Type Codes - B:BGP D:Connected O:OSPF R:RIP S:Static; Cost - Dist/Metric
BGP Codes - i:iBGP e:eBGP
OSPF Codes - i:Inter Area 1:External Type 1 2:External Type 2
Destination Gateway Port Cost Type Uptime
1 100.x.x.0/24 150.x.x.x ve 150 x/x S 18h41m
You can see the outgoing interface is VE 150 and gateway is 150.x.x.x. Then you can do show arp to find out where is 150.x.x.x learned.
FCX_STK_2#show arp 150.x.x.x
1 18.104.22.168 00e0.5200.0100 Dynamic 0 2/1/23 Valid
So the outgoing int is 2/1/23.
Hope this helps,
06-26-2013 11:44 AM
Thanks Deepti that was pretty helpful but now I am trying to look for a command to view the forwarding table of the router.
I tried "show cam ip 1/1 " . This command was per interface. Does not there exist a system wide forwarding table that I can view using a command ?
06-29-2013 07:33 PM
Unfortunately I could not get all the routers on which I am looking for the forwarding tables. I had asked for show version but it does not have what type of router it is. My Bad.
But I remember MLX and ADX. I am looking for info like : Destination , its next hop and outgoing interface in the forwarding table.