Router ISDN question 1

[ciscopix77]

Hi all

This question is about a 3com router but I am sure u can do something similar with a cisco router and I am familiar with cisco routers so have posted this here!
I am not very familiar with 3com routers but I do hope some one can help out. The current settings for the router are that 3 isdn lines are bound together so whichever call comes in uses one of the three lines. My question is how can I set up the router so that these lines won't be bound together and each one will take a separate call with 128kb/s? It's a 3com 5009 router. This is the current router config:

Current configuration
!
3Com Router Software V1.30
local-user xxxx service-type ppp password simple xxxx
local-user xxxx service-type ftp password simple xxxx
local-user xxxx service-type ppp password simple xxxx
sysname xxxxxx
ppp mp binding-mode authentication
dialer-rule 1 ip permit
info-center console
firewall enable
aaa-enable
aaa accounting-scheme optional
ftp-server enable
!
acl 2000 match-order auto
rule normal permit source any
!
interface Aux0
async mode flow
link-protocol ppp
!
interface Ethernet0
ip address 217.xxx.xxx.xxx 255.255.xxx.xxx
nat outbound 2000 interface
nat server global 217.xxx.xxx.xxx 3389 inside 192.168.5.6 3389 tcp
nat server global 217.xxx.xxx.xxx 8080 inside 192.168.5.6 8080 tcp
!
interface Serial0
link-protocol ppp
!
interface Bri0
link-protocol ppp
ppp authentication-mode pap
ppp mp
isdn service data
isdn service speech
dialer enable-circular
dialer-group 1
dialer circular-group 0
!
interface Bri1
link-protocol ppp
ppp authentication-mode pap
ppp mp
isdn service data
isdn service speech
dialer enable-circular
dialer-group 1
dialer circular-group 0
!
interface Bri2
link-protocol ppp
ppp authentication-mode pap
ppp mp
isdn service data
isdn service speech
dialer enable-circular
dialer-group 1
dialer circular-group 0
!
interface Bri3
link-protocol ppp
isdn service data
isdn service speech
dialer enable-circular
!
interface Dialer0
link-protocol ppp
ppp authentication-mode pap
ppp mp
ppp mp max-bind 6
ip address 10.10.10.1 255.255.255.0
dialer enable-circular
dialer-group 1
dialer number ""
!
quit
ip route-static 0.0.0.0 0.0.0.0 217.xxx.xxx.xxx preference 60
ip route-static 10.10.10.0 255.255.255.0 Dialer 0 preference 60
ip route-static 192.0.0.0 255.0.0.0 Dialer 0 preference 60
!
return


cheers

 

[rtfmdude]

Admittedly, I don't know 3com - I'm a cisco-weenie myself, but I do know alot about isdn and ddr on cisco stuff, so, here's my 2centavos. It looks like the isdn interfaces are bound to the dialer 0 interface using the command 'dialer circular-group 0' (which seems like a total rip off of the ios command 'dialer rotary-group,' but who knows cisco coulda ripped it offa 3com. So, what I suggest is to change the different bri interfaces to either:

-use 'dialer circular-group 0' on interface bri0, keeping it bound to interface dialer0, then change bri1 to have 'dialer circular-group 1' and creating an interface dialer1, then doing the same for bri2, configure 'dialer circular-group 2' and then configure an interface dialer2. remember to put different ip addresses and all that stuff on the dialer interfaces.

OR

-simply remove the 'dialer circular-group 0' commands under all the bri interfaces and then try to add the necessary commands to the bri interfaces themselves (in the cisco world, a dialer interface is NOT necessary by default, unless you wanna group many bri interfaces together.

OR

-in a cisco config using the 'dialer rotary-group' command to bind many bri interfaces to a single dialer DOES allow multiple remote sites to connect that same dialer interface by default(it is a multipoint interface vs. a point to point interface) - have you simply tried connecting multiple clients simultaneously? (of course, you'd have to make sure 1 client was connecting using ip add 10.10.10.2, the next was using 10.10.10.3 - no-no on trying to use the same ip address on multiple remotes)

hope that helps!

WHEW - I SHOULD BE OUT DRINKING INSTEAD! ANYONE IN AUSTIN AROUND HERE?

 

[ciscopix77]

Thanks a lot for that! I was thinking the same as ur solution 1. I will definitely give that a go. Then I will need to change the ip address on each dialer interface isn't it? .1, .2 and .3 for example?

For the second solution, what do u mean by add the necessary commands to the bri interfaces?

Sorry if these questions are silly but I am relatively new to the world of ISDN! Thanks for ur help!

 

[rtfmdude]

Yes and no - you'd need to change the ip addresses of the dialer interfaces, but you couldn't just change the last octet - you'd have to make sure they were on unique subnets. so, something like this is BAD:

interface Dialer0
ip address 10.10.10.1 255.255.255.0

interface Dialer1
ip address 10.10.10.2 255.255.255.0

interface Dialer2
ip address 10.10.10.3 255.255.255.0

something like this would be good, and should work:

interface Dialer0
ip address 10.10.10.1 255.255.255.0

interface Dialer1
ip address 10.10.11.1 255.255.255.0

interface Dialer2
ip address 10.10.12.1 255.255.255.0

you could even do this:

interface Dialer0
ip address 10.10.10.1 255.255.255.252

interface Dialer1
ip address 10.10.10.5 255.255.255.252

interface Dialer2
ip address 10.10.10.9 255.255.255.252

as far as the second sol'n, I meant add all the commands on the bri that the dialer interface has that looks necessary for connectivity. So, instead of this(what you have currently):


interface Bri2
link-protocol ppp
ppp authentication-mode pap
ppp mp
isdn service data
isdn service speech
dialer enable-circular
dialer-group 1
dialer circular-group 0

interface Dialer0
link-protocol ppp
ppp authentication-mode pap
ppp mp
ppp mp max-bind 6
ip address 10.10.10.1 255.255.255.0
dialer enable-circular
dialer-group 1
dialer number ""

make it this instead:

interface Bri2
link-protocol ppp
ppp authentication-mode pap
ppp mp
isdn service data
isdn service speech
dialer enable-circular
dialer-group 1
ip address 10.10.10.1 255.255.255.0
dialer number ""

(that looks like it'll work)

 

[ciscopix77]

Thanks ever so much for that! Will give it a go! Is there a reason why they should be on unique subnets? Just curious!

Thanks

 

[rtfmdude]

well, they need to be unique subnets because they are different interfaces. For example, cisco routers don't allow you to configure multiple physical intefaces with the same subnet (unless you've disabled ip routing) - i guess it would be confusing to the router to have multiple interfaces on 192.168.1.X and have some outgoing traffic for 192.168.1.10 - which interface would it choose?

cisco ppp handles things a bit differently, as ppp installs a /32(host) route whenever a connection is successfully established - meaning a lot of times you can screw up an ip configuration and it'll still work(even if the 2 directly connected interfaces are on different subnets).

sounds like you wanna keep everyone on the same subnet - have you tried leaving the config the way it is and just renumber the remotes so that they're 10.10.10.2/3/4? I honestly think that would work fine.

 

[ciscopix77]

Hi again!

When u say leave as it is, do mean as the original post? Just one dialer interface? Or try the suggested ip's (2,3,4) each with a separate dialer interface? A bit confused now...

 

[rtfmdude]

Yeah, when I said:

"sounds like you wanna keep everyone on the same subnet - have you tried leaving the config the way it is and just renumber the remotes so that they're 10.10.10.2/3/4? I honestly think that would work fine. "

I really mean just leave the config the way it is(original post/just one dialer interface/be lazy), and make sure the remotes are 10.10.10.2, 10.10.10.3 & 10.10.10.4. Make sure their default gateway is 10.10.10.1, and let 'er rip.

 

[ciscopix77]

So would it look like this:

interface Dialer0
link-protocol ppp
ppp authentication-mode pap
ppp mp
ppp mp max-bind 6
ip address 10.10.10.1 255.255.255.0
ip address 10.10.10.2 255.255.255.0
ip address 10.10.10.3 255.255.255.0
ip address 10.10.10.4 255.255.255.0
dialer enable-circular
dialer-group 1
dialer number ""

or should the 10.10.10.1 not be there? How do I make the default gateway to 10.10.10.1?

One last question (I hope ) if I decide to use the config with 3 dialer interfaces then it is a must to use different subnets? Sorry about this!

 

[rtfmdude]

no.

basically, it would look like this (helps to draw it out a little):
SINGLE DIALER SCENARIO(config as-is currently)

[3com router]
ipaddr 10.10.10.1(dialer0)
| | |
| | [remote1]ipaddr 10.10.10.2
| [remote2]ipaddr 10.10.10.3
[remote3]ipaddr 10.10.10.4

MULTI DIALER SCENARIO
[3com router]
ipaddr 10.10.10.1(dialer0)
| ipaddr 10.10.11.1(dialer1)
| | ipaddr 10.10.12.1(dialer2)
| | |
| | [remote1]ipaddr 10.10.10.2
| [remote2]ipaddr 10.10.11.2
[remote3]ipaddr 10.10.12.2

different subnets might not be a must, but they'd be a strongly suggested. I would say must.

 

[ciscopix77]

So for the first scenario nothing changes in the original config at all? Just a matter of testing it?
and the second scenario just as u explained above! I think I got it...Finally! Will let u know how it goes...Very much appreciate ur responses!

cheers

 

[ciscopix77]

Just wanted to ask about hese lines:

ip route-static 0.0.0.0 0.0.0.0 217.xxx.xxx.xxx preference 60
ip route-static 10.10.10.0 255.255.255.0 Dialer 0 preference 60
ip route-static 192.0.0.0 255.0.0.0 Dialer 0 preference 60


I should add the route for each subnet? e.g.

ip route-static 10.10.11.0 255.255.255.0 Dialer 1 preference 60

ip route-static 10.10.12.0 255.255.255.0 Dialer 2 preference 60

etc.... And I'm not sure what this is doing:

ip route-static 192.0.0.0 255.0.0.0 Dialer 0 preference 60

thanks a lot!

 

[ciscopix77]

You there? You probably are fed up with me by now...hehe...
Just one last scenario, let's say there are 3 dialer interfaces, int dialer0,dialer1 and 2 using ip's 10.10.10.1, 10.10.11.1 and 10.10.12.1. But let's say the clients that dial in are on the 192.168.x.x subnet. My question is would I have something like this:

ip route-static 192.168.x.x 255.255.255.255 Dialer 1 preference 60

ip route-static 192.168.x.x 255.255.255.255 Dialer 2 preference 60

instead of the above (previous post) 10.10.11.0 and 10.10.12.0?

Thanks a lot once again!

 

[rtfmdude]

whoops - sorry, I actually forgot to respond, I swear


"I should add the route for each subnet? e.g.

ip route-static 10.10.11.0 255.255.255.0 Dialer 1...
ip route-static 10.10.12.0 255.255.255.0 Dialer 2..."

No way - the router should -know- that these subnets exist off of those interfaces because the router's dialer interface 'lives' on those networks.

It would be like, say your house's address is 410 Oak Street, and then you wonder how to get to Oak St.

what you DO need (unless you're NAT'ing) is to add routes to the networks connected to those remote routers, behind the directly connected ISDN interfaces:

[3com]10.10.11.1-bri-10.10.11.2[router]--192.168.1.X

this would result in you needing:

ip route-static 192.168.1.0 255.255.255.0 10.10.11.2

OR

ip route-static 192.168.1.0 255.255.255.0 dialer0/1/2
(out whatever dialer interface really is used for the connection)

-=-=-=-=-=-=above was for the 1st post, and it looks like you had already come to this conclusion on the second post - hehe. nice.

 

[ciscopix77]

Hi

It's me again!! Do u think I will still need this command at the start:

ppp mp binding-mode authentication

and this one in each BRI interface:

ppp mp

I'm asking because we no longer need to bind lines or this does not harm the config?

cheers

 

[rtfmdude]

Well, the clients that are going to dialin are going to use BOTH channels on a BRI, right? If so, then leave these. If not, well, it won't hurt. Leave 'em.