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New Member

Routing

Hello

I need some clarification about routing. If I had these interface address:

10.1.1.1 255.255.128.0

192.168.1.1 255.255.255.240

55.22.1.1 255.252.0.0

when configuring routing what would I enter for the network

eg. #router ripv2,ospf,eigrp

network " "

thanks for your help

14 REPLIES
Silver

Re: Routing

Seems all of them are VLSM. You have to enter the network as same as your mask. e.g. network 10.1.1.0 255.255.128.0

Try to search the Cisco web for command examples

Hope this helps.

Hall of Fame Super Silver

Re: Routing

Jack

I am not sure how you are characterizing these as VLSM. There are multiple addresses given, each in a different major network and each with a different mask. But within any network there is no variability of the mask.

I also believe that a more appropriate answer is that the format of the network statement is highly dependent on the protocol being configured. It has been quite a while since I really worked with RIPv2 but my memory that RIPv2 (like RIPv1) only takes a network statement with the major (classful) network. EIGRP by default will take a network statement with the major classful network but has the option of supplying a mask so that the network statement could match the address or subnet of the interface. And OSPF requires a mask in the network statement. In configuring OSPF there are options so that you could have a mask that matches the major classful network, could have a mask that matches the subnet, and can have a mask that matches the specific interface address (and multiple variations in between).

HTH

Rick

Silver

Re: Routing

Hi Rick,

Thanks a lot for your comment and sharing your idea. I agreed what you mentioned. In my response, I stated VLSM, this is because all stated subnets are not using classful mask, so I treated it as VLSM and we have to include the subnet mask in the routing protocol to ensure it won't overlapped w/ other networks. So I propose the network command w/ mask.

And I also stated to search the examples in CCO to look for the correct command format. Just as you said, different routing protocol will require different command format, so I just list one as example.

I encourage people to search the web to look for the ans. quickly instead of waiting for people's feedback. Do you agree ?

Thanks again for your comment and I like these kind of communication. ;)

Hall of Fame Super Silver

Re: Routing

Jack

I am not sure what you mean about not using classful mask. Each of the networks/subnets mentioned gives a single subnet with mask:

10.1.1.1 255.255.128.0

192.168.1.1 255.255.255.240

55.22.1.1 255.252.0.0

We might perhaps say that it is not traditional masking on octet boundaries (/16, /24, etc) or subnetting in the last octet, but from a single subnet we can not tell whether the masking will be variable length subnet masking (VLSM) or fixed length subnet masking (FLSM). And each of these subnets could be used in a classless manner or in a classful manner. We do not yet have enough information about the network to make those determinations.

I do certainly agree with your point about looking on CCO for examples and for information about correct format. And I absolutely agree that people should be encouraged to look for information that can answer their own questions.

And I do agree that discussions like this are a very helpful part of the forums.

HTH

Rick

New Member

Re: Routing

ospf takes wild card mask

so i think for ospf

network 10.1.0.0 0.0.127.255 area XXX

network 192.168.1.0 0.0.0.15 area XXX

network 55.22.0.0 255.3.0.0 area XXX

for other i think you would configure only major network.

router X.X.X.X

cheers

New Member

Re: Routing

Hello,

I think I understand things better now with regards to OSPF network statements. Another question is IS-IS configuration done the same? Also I want to configire EIGRP with wildcards but it won't allow it I tried the no auto-summary statement but It still wont allow it, how do I turn on wild cards with EIGRP?

also for ripv2 with vlsm, when using network command you would just enter the classfull address eg.

10.1.1.1 255.128.0.0 would be network 10.0.0.0?

thanks for all the help

Hall of Fame Super Silver

Re: Routing

Steven

What version of IOS are you running? EIGRP in older releases did not support wild cards and in newer releases it does support them. If your code supports it you should just be able to enter them after the network address. There is not anything you need to do to enable it (other than be running code that does support it).

HTH

Rick

Silver

Re: Routing

Thanks again Rick for your comment.

I understood what you mean and I think the way of my presentation may misleading you. ;)

New Member

Re: Routing

Hello

ios version 12.0(10).

New Member

Re: Routing

ip summary-address eigrp as-number ip-address wildcard-mask [admin-distance] [leak-map name]

Command History

Release Modification

10.0

This command was introduced.

12.0(7)T

The admin-distance argument was introduced.

12.3(14)T

The leak-map keyword was introduced.

cheers

New Member

Re: Routing

ip summary-address eigrp as-number ip-address wildcard-mask [admin-distance] [leak-map name]

Command History

Release Modification

10.0

This command was introduced.

12.0(7)T

The admin-distance argument was introduced.

12.3(14)T

The leak-map keyword was introduced.

cheers

New Member

Re: Routing

ip summary-address eigrp as-number ip-address wildcard-mask [admin-distance] [leak-map name]

Command History

Release Modification

10.0

This command was introduced.

12.0(7)T

The admin-distance argument was introduced.

12.3(14)T

The leak-map keyword was introduced.

cheers

New Member

Re: Routing

Hall of Fame Super Silver

Re: Routing

Steven

I believe that the code you are running is slightly too old to support the mask option of the EIGRP network statement. According to this link the option was added in 12.0T:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/hirp_r/rte_eih.htm#wp1097696

So if you want to enable the mask option you will need up upgrade the IOS to a newer version.

HTH

Rick

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