From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Sat Jul 24 2004 - 00:01:00 GMT-3
Ken,
Although IS-IS is part of the CLNS stack, it uses its own LSAP
value (0xFEFE), and is transmitted as a CLNS broadcast. The
implications of this are that when transporting IS-IS across an NBMA
media, CLNS resolution must be configured with broadcast support.
However, since the packets are broadcasts, the unicast NET address
configured on the mapping statement is arbitrary.
For example, suppose you have an ATM SVC that is running IS-IS.
interface ATM0/0/0
ip address 54.2.4.6 255.255.255.0
ip router isis
atm esi-address 000000054246.00
pvc 0/5 qsaal
!
pvc 0/16 ilmi
!
!
svc BB1 nsap 47.00000000000000000000000A.000005424254.00
protocol ip 54.2.4.254 broadcast
Rack2R6#debug isis adj-packets
IS-IS Adjacency related packets debugging is on
Rack2R6#
ISIS-Adj: Rec L1 IIH from VC 87 (ATM0/0/0), cir type L1, cir id
00E0.1E57.E592.01, length 4467
ISIS-Adj: Rec L1 IIH from VC 87 (ATM0/0/0), cir type L1, cir id
00E0.1E57.E592.01, length 4467
ISIS-Adj: Encapsulation failed for L2 LAN IIH on ATM0/0/0
Without a CLNS mapping encapsulation fails, hence no adjacency.
Add the mapping with any arbitrary NET and the transport is successful:
interface ATM0/0/0
svc BB1 nsap 47.00000000000000000000000A.000005424254.00
protocol clns 00 broadcast
IS-IS Adjacency related packets debugging is on
Rack2R6#
ISIS-Adj: Sending L1 LAN IIH on ATM0/0/0, length 4467
ISIS-Adj: Rec L1 IIH from VC 87 (ATM0/0/0), cir type L1, cir id
00E0.1E57.E592.01, length 4467
ISIS-Adj: Rec L1 IIH from VC 87 (ATM0/0/0), cir type L1, cir id
00E0.1E57.E592.01, length 4467
Rack2R6#show clns is-neighbors
System Id Interface State Type Priority Circuit Id
Format
BB1 AT0/0/0 Up L1 64 BB1.01
Phase V
Encapsulation successful, adjacency established.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Kenneth Wygand
> Sent: Friday, July 23, 2004 9:15 PM
> To: ccielab@groupstudy.com
> Subject: mapping CLNS over frame or ISDN
>
> I'm a little confused when mapping CLNS over Frame or ISDN to get ISIS
> to work. I know the 'net' variable is one of the attributes that can
be
> configured as part of this mapping, but I don't believe it is
required.
> Is the 'net' attribute available to simply limit the propagation of
CLNS
> packets across a F/R or ISDN circuit when the packets are destined for
a
> net which is not available across the F/R or ISDN cloud?
>
>
>
> For example, let's say I have two nets on a given router, one for area
> 00.0001 and one for area 00.0002. Suppose these are both configured
on
> my single router. Now if I have a F/R or ISDN circuit and I want to
map
> CLNS, do I need to have the 'net' attribute to provide this mapping
for
> CLNS to traverse the circuit? If not, will CLNS packets on both nets
> pass over the circuit? If I specify a particular net, say 00.0001,
then
> will only nets for 00.0001 propagate the circuit?
>
>
>
> Thanks in advance for any explanation.
>
>
>
> Kenneth E. Wygand
> Systems Engineer, Project Services
>
> CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP, CNA,
> Network+, A+
> Custom Computer Specialists, Inc.
>
> "I am not really smart. I just stick with problems longer."
> -Albert Einstein
>
>
>
> Custom Computer Specialists, Inc.
>
> "Celebrating 25 Years of Excellence"
>
> [GroupStudy removed an attachment of type image/gif which had a name
of
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>
>
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