R(Config-R)# NW X.X.X.X Y.y.y.y ==> Is it a network advertisement or enabling RP on that interface?

ashish7aditya · ‎11-16-2016

Dear Experts,

I always have a confusion with below cmd under different routing protocols like RIPv2, EIGRP and OSPF?

Consider a router "R" with 4 different interfaces directly connected to NW 10.0.0.0/8 || 11.0.0.0/8 || 12.0.0.0/8 || 13.0.0.0/8

Example-1)

Under RIP,

R(Config)# router rip

R(Cf-R)#version 2

R(Cf-R)# network 10.0.0.0

R(Cf-R)#exit

Example-2)

Under EIGRP,

R(Config)# router eigrp 10

R(Cf-R)# network 10.0.0.0 0.255.255.255

Example-3)

Under OSPF,

R(Config)# router OSPF 1

R(Cf-R)# network 10.0.0.0 0.255.255.255 area 1

Query: What do we mean by this cmd in pink under different routing protocols (RIP, OSPF, EIGRP)?

Does it mean that it will put the corresponding interface of this router in RIP(Ex-1), EIGRP(Ex-2) and OSPF(Ex-3) and will advertise this network in the direction of router-R's interface 10.0.0.0/8 only? i.e. next hop router connected to NW 10.0.0.0/8 will only receive this advertisement & adjacent routers corresponding to NW 11.0.0.0 || 12.0.0.0 || 13.0.0.0 will not receive this advertisement from router-R (even though corresponding routing protocol is enabled on adjacent router of NW 10.0.0.0 || 11.0.0.0 || 12.0.0.0 || 13.0.0.0).

I will have to write similar network statements for NW 11.0.0.0 || 12.0.0.0 || 13.0.0.0 & then only advertisement of network 10.0.0.0 (& other networks now) will reach in all the four directions of router-R?

OR,

Does it mean that it will advertise 10.0.0.0 network on all the interfaces of this router-R and corresponding next hop routers connected through different interfaces of this router-R in discussion will also learn 10.0.0.0 network?

I haven't written similar network statements for NW 11.0.0.0 || 12.0.0.0 || 13.0.0.0 on this Router-R in discussion. Only one network statement i.e. for NW 10.0.0.0 but I have enabled RIP/EIGRP/OSPF as per the case on all the next hop routers of these 4 networks?

Best Regards!

Paul Chapman · ‎11-20-2016

Hi -

In each of the presented protocols the network statement tells the router which interfaces participate in the protocol. Participation in the protocol means several things:

1) Place the attached network in the associated memory space (topology table, database, etc.) for that protocol for distribution to other routers

2) Look for other routers on the participating interfaces (unless disabled)

Based on your example RIP, EIGRP, and OSPF will all attempt to find peers in the 10.0.0.0 network. Since 10.0.0.0 is the connected network, it won't be advertised because the router does not advertise a connected network to peers in that same network.

If you had peers in 11.0.0.0, 12.0.0.0, or 13.0.0.0, they would not be able to connect to router R until you add the appropriate network statements to the protocols.

Short answer: enables routing protocol.

PSC

Rolf Fischer · ‎11-20-2016

Duplicate post: https://supportforums.cisco.com/discussion/13167536/rconfig-r-nw-xxxx-yyyy-it-network-advertisement-or-enabling-rp-interface