32. CISCO CML Static route Next-hop vs Exit(Outgoing) Interface
I always uses next-hop instead of exit interface for static.
but, I found static route using exit interface in other site configuration
cisco uses cef technology that has fib and adjacency table
FIB is from Routing table
Connected, Static, Dynamic Routing Protocols.
ADJ is from ARP for Mac address
MAC address
When you to communicate with hosts belong to connected interface like vlan, ARP is required to get mac address.
even between two routers, they need mac address of next hop router.
Scenario 1 - Point to Point
verify the difference between next-hop and interface
arp time 10 (second) on the interface
no keepalive
no cdp enable
1.next-hop
arp request for next-hop(192.168.254.2)
2.interface
arp request for hosts(192.168.2.0 - 255)
I think this is not good because it consumes memory for arp table and cpu resource for ARP request
the next-hop router reply the arp request because acting as proxy-arp
to disable this, use 'no ip proxy-arp' on the interface
Scenario 2 - Point to Multipoint
1.interface
same as scnario 1
you need to carefully consider to use 'proxy-arp' because of cpu resource
no ip proxy-arp will be preferred in normal situation.
let's check recursive lookup for next-hop later.