ip route 10.10.1.0 255.255.255.0 fa0/0 10.200.1.1 – combination of i/f and next hop
ipv6 static routing:
(config)#ipv6 unicast-routing
interface fa0/0
ipv6 enable
ipv6 address fec0:0:0:3::/64 eui-64
IPv6 show commands:
show cdp neighbor details
show ipv6 interface fa0/0
show ipv6 route -> L indicates locally connected
If global IP addresses are re-numbered, link-local addresses remain the same. If the router has to be replaced, routing has to be reconfigured (if routes point to link-local addresses)
IPv6 never responds to PROXY-ARP
Alternate routes: static routes with a higher cost (influences the AD)
Load sharing: per packet/ per destination. Per packet is obviously a more ‘fair’ load-balance but may cause packets to arrive out of order. This maybe unacceptable for real-time applications like VoIP.
CEF: uses 2 tables FIB (L3 derived from routing table) and Adjacency table (L2 from ARP and NS). The tables are built even before the first packet needs to be routed.
Default : per destination (src & dest)
sh ip cef; sh ipv6 cef
at the interface: ip load-sharing per-packet
|
Ingress i/f |
egress i/f |
s/w ing method |
| CEFCEF
Process Process Fast Fast |
ProcessFast
CEF Fast CEF Process |
CEFCEF
Fast Fast Fast Process |
Fast Switching: Only done per-destination. 1st packet -> route table lookup, select egress i/f. -> L2 encap. Store this info in a cache (F.S cache). Subsequent packets use the cache.
Process Switching: IPv6 default. Only process s/w’ed packets show up in debug ip packet. Sometimes even if CEF is enabled, the packets are process sw’ed. Eg: access-list logging.
Recursive route lookup: when the gateway for a route is not directly reachable.
