EIGRP Network command

Hi

Just trying to clarify exactly what the requirements are for the "network x.x.x.x x.x.x.x command are:

I have come across an example showing:

network 10.2.2.2 0.0.0.1 (which is a serial point-to-point link) - 10.2.2.2 /31 is the address stated on the link. The i/f of the remote router must have the address 10.2.2.3 /31 from this mask.

This address encompasses both ends of the link but is it necessary to specify 0.0.0.1 rather than 0.0.0.0. (there are no other networks in that range in this particular example)?

TIA.

Find more posts tagged with

Free for TechExams community: Cybersecurity salary guide

Compare cert salaries and plan your next career move

Button

Comments

networker050184

No, there is no need to specify 0.0.0.1. All the network command is doing is telling EIGRP what interfaces to run on. I always use 0.0.0.0 masks becasue it makes things cleaner and eaiser to read in my opinion.

josunin75

BTW isn't the subnet mask supposed to be /30 not /31?

cisco_trooper

You can use /31 on point-to-point links that are not on multi access media such as ethernet....

dtlokee

we use /31 on uplinks between switches which are Gig-E. Just be careful with the mbecause not all devices will support them.

I like to use the "network x.x.x.x 0.0.0.0" style network command when configuring EIGRP unless the device has many interfaces then I may wildcard them.

marco71

As far as I know, Cisco planning to use /31 mask for frame-relay connections; for point-to-point links, a /30 mask is used, because only two ip addresses are needed...
anyway, for wildcard-mask, a 0 means that the digit from that position must match, and 255 means that the digit does not matter (this is obvious when you want to include more than one interface into EIGRP domain with a single network statement); you can also think at wildcard-mask like the inverse of the subnet-mask, so for 10.2.2.2/30network, the command is network 10.2.2.2 0.0.0.3...
For OSPF, wildcard-mask is mandatory, but for EIGRP, it is not necessary

aragoen_celtdra

cisco_trooper wrote:

You can use /31 on point-to-point links that are not on multi access media such as ethernet....

dtlokee wrote:

we use /31 on uplinks between switches which are Gig-E. Just be careful with the mbecause not all devices will support them.

Interesting. Excellent bit of info. I thought maybe trooper is over-studying

and dt studied too much for his CCIE that he started making things up for himself.

However, they are right and here are some documentation I found from Cisco and the accompanying RFC document. Good fill-in knowledge.

telco1

just make sure you put the IP classless statement in global mode if your IOS doesnt support it by default. that bit me in the but on a couple of labs in the past.