Enabling mobile IP on MSFC2

sagar.shetty · ‎06-16-2005

I have a campus network with cat 6500 with MSFC2. I want to provide 10 of my IPs in vlan 7 to roam in vlan 4. How can I achieve this.

Is the following config suffice or have I to add something more.

router mobile

int vlan 4

ip mobile foreign-service

ip mobile home-agent

ip mobile host 10.3.11.13 10.3.11.20 interface Vlan7

ip mobile foreign-agent care-of Vlan4

dknov · ‎06-16-2005

Hi,

I am not sure about this config, but you can use another feature of Mobile IP called LAM (local area mobility). You can find references describing this features and also some template configs.

I have tested it a few times and it works like a charm!

Note some ARP considerations when you read the docs. You might need to manually clear the ARP table on keep it consistent with proxy-arp operation...

David

sagar.shetty · ‎06-17-2005

hi,

LAM seems to a simpler. But does it need a routing protocol to be enabled with redistribute mobile, if I am using in the same LAN network.

Well , as per the template I have configured it as follows,

int vlan 3

ip mobile arp

int vlan 4

ip mobile arp

But this didnot work for me. I tried redistributing mobile in ospf. But still didnot work.

dknov · ‎06-18-2005

Hi,

1. Yes, you need to redistribute Mobile route to your IGP in case you have clients connecting to different L3 boxes (if it's the same box then all Mobile prefixes will be like Connected)

2. You mentioned it's not working, so let see the following:

a. If you do "show ip route mobile" do you the

prefixes marked with M?

b. All IP stack info should be configured

manually and through any dynamic means such as

DHCP

c. Do you have proxy-arp enabled on inbound

interfacesof both VLAN4 and VLAN7?

d. LAM has a strong dependancy on ARP (proxy arp

to be exact), so ARP caching on workstation

can really mess it up. Try to clear arp cache

(arp -d on Windows) tables on all workstation

trying to communicate through LAM.

If A wants to communicate with B which have roamed from the "home" subnet. After clearing ARP tables on both A and B you should see the following:

i. A should show MAC address of B as MAC address of A's default gateway router

ii. B should show its default gateway MAC as being MAC address of the default gateway where he had roamed.

iii. B should show MAC addresses of all workstations on his "home" subnet as having MAC address of the default gateway where he had roamed.

It's easy to break LAM because of this arp caching. There might be a registry tweak to set the arp cache timer to 0, meaning NOT to cache.

David

sagar.shetty · ‎06-19-2005

Hi David,

I could fine no routes marked with 'M' and as mentioned proxy-arp is enabled. When i look for the arp entry in the MSFC2, I can see the correct vlan entry in which the machine is roaming. The only catch is that the mobile route is not getting triggered.

Also, I would like to tell, I have HSRP enabled. Is it causing any problem.

sagar

dknov · ‎06-20-2005

Hi,

Do you have IP address/Mask/Gateway statically configured on roaming pc?

David

sagar.shetty · ‎06-20-2005

Hi,

Yes I have it configured statically.

sagar

dknov · ‎06-21-2005

Ok, let's do the following test:

PC1 is in home VLAN, PC2 is in roaming (foregn) VLAN

DG2 is a default gateway router of a foregn VLAN.

1. Take PC2 and do "arp -d" on it (erase ARP cache)

2. Move PC2 to foregn VLAN where proxy-arp and LAM

are configured on default gateway router (DG2)

3. PING from PC2 towards PC1

4. Do "arp -a" on PC2.

5. Verify that you see on PC2 that physical address

that corresponds to PC1 equals to a physical

address of a DG2

I am trying to see why you don't see "M" entries in a routing table...

sagar.shetty · ‎06-21-2005

I carried out this test.

Cleared the arp entries of the roaming PC and moved it into new Vlan where LAM and proxy-arp is configured.

Sent a ping to one of the home PC and checked the arp entries. It gave the mac address of the VLAN interface in which it is placed for the home PC IP.But no ping replies.

When checked for the arp entries on MSFC2, it showed the physical address of the roaming PC in the vlan in which it is placed (i.e., roaming vlan).

When no mobile routes were observed in the routing table.

sagar.shetty · ‎06-21-2005

forgot to mention, when a static route of roaming PC was added, the roaming PC was reachable and all the network was reachable. But dynamically route is not getting added.