From: Klaus Mueller (klausm@xxxxxxxxxxx)
Date: Sun Jul 04 1999 - 00:17:06 GMT-3
Ben,
The config you show uses Multiprotocol encapsulation over ATM AAL5 (RFC
1483). Using RFC1483 you can basically use ATM similar as you would
frame-relay in a wide area scenario. Each PVC is basically a point-to-point
"circuit" between two end devices - probably routers. RFC1483, as the title
suggests, will also support multiple protocols so you can configure the
interface with IP, IPX, bridging, etc... just as you would frame-relay or
other wide-area links.
Here is an example of another way of configuring a routers to communicate
over a PVC through an ATM switch, in this case using subinterfaces:
interface ATM0/0
no ip address
no ip directed-broadcast
!
interface ATM0/0.32 point-to-point
description VBR PVC - LIS to Gibson
ip address 172.24.254.6 255.255.255.252
atm pvc 32 1 32 aal5snap 6150 6150 oam 10
bridge-group 1
!
interface ATM0/0.33 point-to-point
description LIS to Journal Center
ip address 172.24.254.10 255.255.255.252
atm pvc 33 1 33 aal5snap 16970 16970 oam 10
bridge-group 1
In the above there are two PVC's, each going to a different site. The
config on the routers on the opposite ends are similar.
In my opinion you would use RFC1483 configuration anytime you are using ATM
as a wide-area transport (router to router) with PVC's. In the above
example is taken from a router that connects to USWest's ATM cell relay
service.
As far as using LANE goes, my understanding is that it is useful when you
are trying to interact with a more traditional broadcast LAN environment.
One instance may be where you have an ATM infrastructure and you connect
servers or workstations directly to the ATM using ATM NIC's. The servers,
etc... would need to use LANE to communicate to other devices on the ATM
network and to devices on Ethernet segments, etc... Another use for LANE
is as a trunking mechanism for multiple VLAN's. In this case, Ethernet
switches - with multiple VLAN's configured - would be uplinked to an ATM
infrastructure. Each VLAN would map to an ELAN ("Emulated LAN") on the ATM
backbone. Presumably the ATM would ultimately also connect to a router
which would perform the layer 3 routing functionality between the
ELAN's/VLAN's. Using LANE here basically extends the layer 2 switching
between the Ethernet switches and the ATM backbone.
- Klaus
-========================================================-
Klaus Mueller e-mail:
klausm@netarch.com
Network Architechs
Albuquerque, NM
-----Original Message-----
From: Niall <niallr@ibm.net>
To: Ben Rife <brife@bignet.net>
Cc: Scott F. Robohn <sfr@ccci.com>; ccielab@groupstudy.com
<ccielab@groupstudy.com>
Date: Saturday, July 03, 1999 11:44 AM
Subject: Re: ATM
>Caslow's book gives a reasonable explanation of when you would want to use
LANE.
>Specifically, whenever you want to run more than IP over the ATM network.
I'm
>getting some good hands-on time at work doing this on 10 5500s :-) I've
also
>been reading Berry Kercheval's TCP/IP over ATM (ISBN 0-13-768599-8). It has
>helped me get a MUCH better grip on how some of this stuff works.
>
>In the lab we won't have to config the switches, just the edge devices like
the
>Catalysts. At least that is my understanding.
>
>Niall
>
>Ben Rife wrote:
>
>> 10 days left !!!
>>
>> Scott and other list members,
>>
>> I appreciate your response to my ATM questions about a week ago. I
need
>> to discuss something else with you though, if you have time.
>>
>> Looking through the doc cd and cco, I have found examples for configuring
an
>> ATM PVC between 2 routers, through a switch. The config of the interface
is
>> as follows (similar at both ends):
>>
>> ROUTER:
>>
>> interface atm 0
>> ip address 1.1.1.1 255.255.255.0
>> atm rate-queue 1 100
>> atm pvc 5 0 10 aal5snap
>> map-group atm
>> !
>> map-list atm
>> ip 1.1.1.5 atm-vc 5 broadcast
>>
>> This doesn't appear to be using LANE, can you explain why? When and why
do I
>> need LANE? This config is very simple. Even the switch config is simple.
>>
>> As for the CCIE Lab, cco says that with respect to ATM, we will not have
to
>> configure a switch at this time. Does this mean that we won't be using
LANE
>> in the lab?
>>
>> Thanks everyone, have a happy and safe 4th,
>>
>> Benjy Rife
>> MCSE, CNE, CCIE Candidate
>> brife@bignet.net
>> www.bignet.net/~brife
>>
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