Large scale dial in

[ccobtn]

We are design large scale dialling for a client, they have 608 remote sites dial into two 3660 routers, each one have 10 pri line. It's only dial in and may dial out in future.

We are thinking of using OSPF between the 3360 routers and creating 608 profiles for each remote on both 3660 router, instead of this can you just have a generic dial profile of all remote sites, as this would make config much easy to manage.

Other problem is routing updates the remote sites all have different ip address schemes. The Cisco 3660’s need to exchange routing table so that if a remote dials in say first 3660, the routing table should be update on second 3660 routers. The reason for this is that we planning to HSRP between the 3660 routers, active standby mode.

There is 2620 router which sits behind the two 3660 router and will have hsrp address as the default gateway no OSPF no this router, it’s outside our control. A call comes and the slave 3660 processes it, and forwards to the 2620. The return packet is sent to active which doesn’t have the call, it will lookup it’s routing table see this via slave router.

Is this a correct solution?.

Thanks

[mljohnson]

You should only consider dialer profiles if you NEED to have per-user configurations (ie each remote will have different characterstics), AND you want to control this on the NAS. If you DON'T need per-user configs, then you don't need dialer profiles and you can do everything on the 3600's. If you DO need per-user configs, you can consider using an external AAA server and virtual-profiles, which is easier to manage than dialer profiles.

Note that when a remote dials in we will install a static route for whatever address was negotiated for the remote. So if you simply redistribute static routes then the 2 3600's will exchange the info for the remote users. Note that the master 3600 will send a redirect to the 2620 since the master 3600 should have never recieved a packet that is actually destined for the slave 3600. HSRP ONLY makes sense in a backup scenario, IE when only one device is accepting calls. If you don't control the 2620, it might be best to put your own small 2600 between the 3600's and the 2620.

[ccobtn]

Hi,

Thanks for your reply......

The only thing that i'm sure is about routing, the remote sites use Mitel Kontac

which is just an ISND with ethernet ports. They have no routing capability

The question is how to set defaulty gateway for remote sites since they all have different subnets???.

[mljohnson]

I don't know how to configure the Mitel's; I would guess that (best case) they use a default interface of the ISDN, and (worst case) they ARP for everything. Either way, they should take care of themselves. The problem will be ensuring that the 3600's know about the devices off the remote ethernets. If the Mitel's use the same address for both ports (similar to IP unnumberd on cisco) then the main site will learn about the IP address of the Mitel and install a host route for that address. However, the main site will not know anything about the ethernet subnet; what you would have to do is to configure (either via the CLI or an external AAA server) static routes pointing to the host address. Once the host address is installed after a remote dials in, the static route would take effect, too.

So let's say remoteA has an address (used by both the ISDN and ethernet ports) or X.X.X.X with a subnet of 255.255.255.240. Then you would want to configure this static route at the main site:

ip route X.X.X.Y. 255.255.255.240 X.X.X.X

Where Y is the subnet byte.

[ccobtn]

Hi,

Another problem we come across is the Remote Mitel needs gateway pointing to one of the 3630's routers, say 3620-A which install static route of Mitel ip add. What Happens If next time the Mitel dials to 3620-B, the mitel gateway points to3620-A hence will not able to communicate Central site. Do you know if there any solution for this problem ????.

Thanks

Abdi

[mljohnson]

Again, I don't know the Mitel that well but you should be able to "fool" it. Keep in mind the next hop address (or default gateway) is really only relevant to the Mitel, and the cisco will not know the better. So, for example, if the Mitel has a default gateway address of 1.1.1.1 pointing to the ISDN interface, then it will send all packets out the ISDN interface, without manipulating the destination address (ie it won't change the dest address to 1.1.1.1). Bottom line, if you can specify an interface as a default route on the Mitel then there should be no problems; if you can't, then use a "dummy" address that is staically mapped to the ISDN interface, and this should work around the problem. Sounds like you should either test this in lab or check with the Mitel folks.