From: Aaron K. Dixon (adixon@xxxxxxxxxxxxxxxxx)
Date: Sun Jul 23 2000 - 04:42:22 GMT-3
Unfortunately, the most logical way isn't normally what you see in the lab
from what I hear. One of the first rules of the lab is that you aren't
allowed to use any static routes of any kind unless specifically told that
you can. This includes floating static routes and if you are asked to
set-up DBU and aren't specifically told to use them you will get this wrong.
I hadn't even thought of that and probably would of missed it on a lab. I'm
so used to setting up DBU with floating static's that I would of used that
method. In the CCIE power session they pointed out that a lot of people
used static routes for their ISDN back-up and didn't get credit.
Regards,
Aaron K. Dixon
-----Original Message-----
From: Keith Kruepke [mailto:lister@kruepke.com]
Sent: Sunday, July 23, 2000 1:25 AM
To: Aaron K. Dixon
Cc: ccielab@groupstudy.com
Subject: Re: EIGRP over ISDN
Aaron,
Yeah, I was assuming that there would be floating statics on both ends, so
that traffic could be initiated each way. But if you did not want to put
floating static routes at the hub, this would be a way to do it. I still
think it would make more sense to use floating statics on both ends.
Thanks,
Keith
----- Original Message -----
From: "Aaron K. Dixon" <adixon@smc.omnes.slb.com>
To: "Keith Kruepke" <lister@kruepke.com>; "Sawal, Vijay"
<Vijay.Sawal@CWUSA.COM>; <abdul_rahim@ccsi.canon.com>
Cc: <ccielab@groupstudy.com>
Sent: Saturday, July 22, 2000 5:42 PM
Subject: RE: EIGRP over ISDN
If you only apply a floating static on the remote router there won't be a
path back without a static route on the hub router or a dynamic routing
protocol. If you use a floating default route the remote router will pass
all traffic across the liink when it it active, but how does traffic return?
If a user is on a LAN segment and tries to get out over the ISDN line the
packets will arrive at the destination, but there won't be a route back
since the Ethernet segment isn't directly connected. There are 2 ways to
solve this problem. One would be to place a floating static route for the
LAN Segment at the hub router pointing across the ISDN line or use a dynamic
routing protocol once the link is established to share routing information.
Regards,
Aaron K. Dixon
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Keith Kruepke
Sent: Saturday, July 22, 2000 5:08 PM
To: Aaron K. Dixon; Sawal, Vijay; abdul_rahim@ccsi.canon.com
Cc: ccielab@groupstudy.com
Subject: Re: EIGRP over ISDN
But I am wondering this...
Yes, you do get neighbor relationships when the line is up. And yes, EIGRP
will not keep the line up. So this does work as claimed. But...
If you are using a floating static to get traffic across the ISDN line, why
would you need EIGRP across that line? Traffic has to get across whether or
not the line is up, so the floating static takes care of that. Is there any
reason at all to use EIGRP on the ISDN link?
Thanks,
Keith
----- Original Message -----
From: "Aaron K. Dixon" <adixon@smc.omnes.slb.com>
To: "Sawal, Vijay" <Vijay.Sawal@CWUSA.COM>; <abdul_rahim@ccsi.canon.com>
Cc: <ccielab@groupstudy.com>
Sent: Friday, July 21, 2000 9:01 PM
Subject: RE: EIGRP over ISDN
You have to keep in mind that interesting traffic only defines the traffic
that will initiate dialing and keep the link active. If you deny eigrp in
the dialing list this doesn't affect traffic once the link is active. Once
the connection is up eigrp will form the neighbor relationship.
Regards,
Aaron K. Dixon
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Sawal, Vijay
Sent: Friday, July 21, 2000 7:30 PM
To: 'abdul_rahim@ccsi.canon.com'
Cc: 'ccielab@groupstudy.com'
Subject: RE: EIGRP over ISDN
But this will not allow EIGRP neighbor relationship to be established
between the two Routers?
Vijay
-----Original Message-----
From: abdul_rahim@ccsi.canon.com [mailto:abdul_rahim@ccsi.canon.com]
Sent: Friday, July 21, 2000 8:02 PM
To: Sawal, Vijay
Cc: 'ccielab@groupstudy.com'
Subject: RE: EIGRP over ISDN
If you use an extended access-list then we have the option to writa an ACL
as folloes
access-list 100 deny eigrp any any
access-list 101 permit ip any any
I hope that helps
Abdul
"Sawal, Vijay" <Vijay.Sawal@CWUSA.COM> on 07/21/2000 04:49:31 PM
To: Abdul Rahim/IS Operations/Operations/CCSI
cc: "'ccielab@groupstudy.com'" <ccielab@groupstudy.com>
Subject: RE: EIGRP over ISDN
All,
This is w.r.t EIGRP over ISDN. I have a question here. As the IP traffic is
interesting, don't u think that
EIGRP Hellos will keep the Link up?
Vijay
-----Original Message-----
From: abdul_rahim@ccsi.canon.com [mailto:abdul_rahim@ccsi.canon.com]
Sent: Friday, July 21, 2000 6:14 PM
To: Walid Fahme
Cc: ccielab@groupstudy.com
Subject: RE: EIGRP over ISDN
The ideal timer is the time with refrence to Interesting traffic only ,No
matter how much the uninteresting traffic is there after the idle timer the
link will go down
Abdul
Walid Fahme <aub95@emirates.net.ae> on 07/21/2000 02:47:36 PM
Please respond to Walid Fahme <aub95@emirates.net.ae>
To: "ccielab@groupstudy.com" <ccielab@groupstudy.com>
cc: (bcc: Abdul Rahim/IS Operations/Operations/CCSI)
Subject: RE: EIGRP over ISDN
Thanks Rick. I think you have a point. The Hello packets should establish
neighbor relation once the link comes up again. But don't you think the
hello packets will keep the link up ? Or uninteresting packets will not
clear the idle timer ??????
Ciao,
Walid.
Look more carefully at his example. His access list did not discard
Hello packets, it merely made them uninteresting. If the link is
down, Hello will not bring it up. If the link is up, hello will be
exchanged and neighbor relationship will form and routes will be
advertised.
Rick
On Fri, 21 Jul 2000, Bill Dicks wrote:
> If you filter the Hellos, then how will the two routers become neighbors
> unless the line is already up? If they don't become neighbors, how will
> routing occur and routes be exchanged?
>
> I see you have the floating static, so if your link to the WAN goes down,
> this will be the only route. BUT, since you are filtering eigrp, you
will
> never become neighbors with the other router on the other side of the
ISDN
> link and no routes will be exchanged. If you're going to use a floating
> static, use 0.0.0.0 so that all traffic goes that way (assuming of course
> that you have a normal 0.0.0.0 route when the WAN link is up). But
without
> Hellos, no neighbor and no routes.
>
> Bill
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Wojtek Iwanczyk
> Sent: Friday, July 21, 2000 1:08 PM
> To: aub95@emirates.net.ae; ccielab@groupstudy.com
> Subject: Re: EIGRP over ISDN
>
> Here is a sample config of DDR using EIGRP ... Filter eigrp "helo s" with
> the dialer list referencing an extended ip access list ...
>
>
> interface Dialer0
> description ISDN Dial-up to NY-PRI-BRI-Router
> ip unnumbered Loopback0
> no ip directed-broadcast
> ip nat outside
> encapsulation ppp
> bandwidth 2
> delay 6000
> dialer remote-name Router1
> dialer idle-timeout 90
> dialer string xxxxxxxxxxxxxx
> dialer string xxxxxxxxxxxxxx
> dialer pool 1
> dialer-group 1
> pulse-time 0
> ppp authentication chap callin
> ppp chap hostname xxxxx
> ppp chap password xxxxx
>
> router eigrp 1
> network 172.31.0.0
> no auto-summary
>
> ip route 172.31.0.0 255.255.0.0 Dialer0 240
>
>
> access-list 160 deny udp any any eq snmp
> access-list 160 deny eigrp any any
> access-list 160 permit ip any any
>
> dialer-list 1 protocol ip list 160
>
> Wojtek Iwanczyk
> Sr Support Engineer
> Exenet Technologies
> 15 E 26th Street
> New York, NY 10010
> (212) 684 7300
> wiwanczyk@exenet.com
>
>
> >>> Walid Fahme <aub95@emirates.net.ae> 07/21/00 01:14PM >>>
> Question:
>
> To limit Distance Vector Protocol updates on a dialup link (ISDN) we
> have several options (Snapshot, Watch-Group)
>
> To limit Link State OSPF updates ==> "ip ospf demand"
>
> What about EIGRP, any solution ???
>
> (Also, is there anything for IS-IS, NLSP and others ????)
>
> Appreciate your comments.
>
> Walid Fahme.
>
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