Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Local Area Mobility

I am having troubled with the local area mobility. Using two different networks over frame relay. I have setup the LAM according to the articles posted with access list, EIGRP.

I have setup a computer on network 1 with a network 2 address. Added the address to the access lists on both networks.

The computer is showing up in the IP route table on network table as a "D" code. And on network 1 showing up in the IP route table as a "M" code for mobile.

I have done a show arp and network and it is showing up there. My problem is that I can not ping the address or even get to that computer on either network.

Does anyone have any suggestions in getting this to work?

14 REPLIES
Anonymous
N/A

Re: Local Area Mobility

not sure of the issue, check out if the following link helps :

http://www.cisco.com/en/US/tech/tk722/tk721/technologies_white_paper09186a00800a3ca5.shtml

New Member

Re: Local Area Mobility

Yes that is exactly what I am trying to do.

But running into an issue that after I get all the commands in it will see the IP address mobile but it can not get to anything on the network.

I am trying to work with cisco but they are trying to tell me that they do not support anymore. But I have found a case study done in 2004 with it work so I don't know what to do.

Looking for someone that is currently using it. If at all.

thank you for responding

New Member

Re: Local Area Mobility

Also I will try and attach the case study. here on this post.

Re: Local Area Mobility

You need to have proxy-arp feature enabled on the router ethernet interface to which the PC is attached to. You can verify whether proxy-arp enabled with the command 'show ip int (ethernet int)'. Also, make sure the PC has a default gateway set for whatever subnet it is on

Pls. rate all helpful posts.

HTH,

Sundar

New Member

Re: Local Area Mobility

Thanks for the proxy-arp tip but, it has been enabled and I also enabled the local proxy arp.

When I do a show ip route it is showing up as a mobile route. and on its home router it is showing it as external eigrp.

So the routers are seeing that it needs to over on the other router but it can not be accessed by the local or remote.

Is there anyone using Local Area Mobility on their systems?

Thanks for the help.

New Member

Re: Local Area Mobility

Make sure you redistribute the mobile host route in your EIGRP domain. The host route will appear as D EX in the other routers' routing table. Another tip is to remove all access-lists from LAM configuration to isolate the issue. Local proxy arp is not needed.

New Member

Re: Local Area Mobility

Thanks for the reply.

I do have all that in place and get the D EX in the routing table and also the M in the other router.

I have redistribute is enabled also.

I get everything setup and it acts like it wants to work but it isn't broadcasting like it should. the routers have it in its routing table but still can't ping the device.

Does any one have any other suggestions.

Hall of Fame Super Silver

Re: Local Area Mobility

Tim

Do I understand correctly that it is showing up in the ARP cache of the router on the segment where it is attached? (I believe that it must for it to show up in the EIGRP routes of the other router.)

If it is ARPing then I believe that it should communicate. Is it possible that there is a firewall running on the PC that is denying ping attempts?

Perhaps it would help if we knew a few specifics: what is the LAN interface address on the router? what is the IP address on the PC? What is the default gateway on the PC? Is the PC able to ping the router LAN interface address? Is the PC able to ping its default gateway?

And as I think about it, I believe that I do not agree with a statement made earlier about the default gateway on the PC that it should be the address on the router on the segment where it is connected. I believe that the PC gateway should be the gateway on the segment where its address logically belongs.

HTH

Rick

Re: Local Area Mobility

Just wanted to clarify.

I mayn't have worded it correct but what I meant was the default gateway of the PC has to be gateway of the logical (IP) subnet it's on. It's not logical to configure the gateway to be on a different IP subnet from the one the PC is on.

When the PC ARPs for the gateway the router interface configured with the 'ip mobile arp' command would proxy ARP and act as the gateway for the PC and life should be good.

Pls. rate all helpful posts.

HTH,

Sundar

Hall of Fame Super Silver

Re: Local Area Mobility

I agree with Sundar. The PC gateway should be consistent with the subnet of the PC address. And when the PC sends ARP for its gateway the local router will respond based on proxy ARP. And as I look back at the posts the statement that I was remembering may be a bit ambiguous. I remembered it as indicating the gateway should be the subnet on which it was connected. But the statement could also be interpreted as indicating that the gateway should be in the subnet of the IP address of the PC.

HTH

Rick

New Member

Re: Local Area Mobility

Okay I am going to try to explain what I have setup so far.

Laptop computer IP: 192.168.2.250 Subnet:255.255.255.0 Gateway 192.168.2.1

Router1 IP: 172.16.0.254 Subnet 255.255.0.0

Router2 IP: 192.168.2.1 Subnet 255.255.255.0

I have configured both routers with Local area mobility directions that cisco has provided. Put the Laptop in the router 1 subnet. Router 1 has the arp entry in its table. In the show ip route it has the entry in there as a mobile node and points back to router2.

In Router 2 the entry shows up in the ip route as D EX as was asked about in a previous message.

When I have the laptop as a local IP address I can ping it with out a problem and remote desktop to it also. The routers also can not ping the device.

I will attach part of the configs if that will help.

Is any of you currently using this?

Here is what I am trying to do with this, I have server on router1 and a backup server on router2 if for any reason that I should lose the main server i will do a rollover on the backup and it will take the IP address of the main and the users won't which system they are on.

Is there a better way of doing this? Mobile IP won't work on this cause of the system that I am using (AS/400).

So any suggestions or is anyone else doing something like what I am trying to accomplish.

Also, I have had this working when I had the routers sitting next to eachother and using the Fastethernets hooked together. So now we are going over a serial connection, could that be our problem? Does the serial support this kind of protocol? Why I question that is that all the information that I have seen is on the Fastethernet and nothing on the Serial connection.

Thank you everyone for your response in trying to solve this issue.

I have attached copies of the configs.

New Member

Re: Local Area Mobility

Hi,

I have my own dilemma... :)

Is Local Area Mobility not supported in Catalyst layer 3 switches (e.g. 3550, EMI)?

I don't have the command ip mobile arp.

Gabriel Gearip

Hall of Fame Super Silver

Re: Local Area Mobility

Gabriel

If you do not have the command ip mobile arp then you do not have the feature. I did a quick search on the software advisor on CCO and do not find a clear answer whether it is supported on layer 3 switches or not. I am guessing that this is one of several features that are routinely part of "router" code that are not included in "layer 3 switch" code.

HTH

Rick

Hall of Fame Super Silver

Re: Local Area Mobility

Tim

I have looked at the configs that you posted and nothing jumps out which would explain your problem. I would suggest, as an experiment, that you remove the access-group from the mobile arp command on both routers and see if that changes the behavior.

It is entirely un-related but I noticed access list 101 which has a single line which denies EIGRP. This access list is used in the dialer-list 1 which ties back to dialer-group 1 on the async interface. The dialer-group and dialer-list identify interesting traffic for the dialer function. Interesting traffic will initiate dial activity and interesting traffic will reset the inactivity timer to keep the connection up. Since the access list denies EIGRP and does not permit anything, you have no interesting traffic, and I suspect that your dialer does not work.

Try removing the access-group on mobile arp and let us know if it changes anything.

HTH

Rick

344
Views
0
Helpful
14
Replies