Subject: Re: (ION) NHRP Queries

From: "Albert Manfredi" <[email-masked]>
Date: Mon, 5 Oct 1998 15:20:48 -0400

What you're describing is the case in which an ATM backbone is
setting up shortcuts between edge IP routers. Sure. If the ATM net
is just a backbone net, or if one of the end users is non-ATM, the
non-ATM user(s) will connect to the ATM backbone via IP routers.
These routers must also be NHSs if you're using NHRP. And the edge
routers are also behaving as NHCs, in that they are setting up a
shortcut between _themselves_.

Any intermediate NHSs would be behaving in the traditional NHS role.
Used only to initially find an IP route between the extreme points
within the ATM net.

In principle, the NHRP part of the ATM backbone doesn't even have to
all be NHRP compliant. Some of it could just be RFC 2225, for
example. So it is really the edge IP routers of the NHRP island(s)
that behave as NHCs as well as NHSs.

Bert
[email-masked]

-----Original Message-----
From: Archana Nehru <[email-masked]>
To: Diane Schuster <[email-masked]>
Cc: [email-masked] <[email-masked]>
Date: Monday, October 05, 1998 1:48 PM
Subject: Re: (ION) NHRP Queries

>Hi,
>Thanx for the response.Please see my comments below:
>
>Diane Schuster wrote:
>>
>> Archana,
>
>> I can't think of any reason why a pure NHS would need to accept
or set
>> up a shortcut. That does not, however, mean that it will not need
to be
>> able to accept incoming SVCs (e.g. from other NHS's and rom it's
NHCs)
>> for the exchange of control data.
>
>The NHRP specs seems to suggest this wherever it talks about
finding an
>"egress NHS", especially if the "destination" is not directly
connected
>to an ATM network.
>
>For e.g: in section 2.2, last para, it says "
>   The Route Record extensions are the NHRP Forward Transit NHS
Record
>   Extension and the NHRP Reverse Transit NHS Record Extension.
They
>   contain the internetwork (and subnetwork layer) addresses of all
>   intermediate NHSs between source and destination and between
>   destination and source respectively.  When a source station is
unable
>   to communicate with the responder (e.g., an attempt to open an
SVC
>   fails), it may attempt to do so successively with other
subnetwork
>   layer addresses in the NHRP Forward Transit NHS Record Extension
>   until it succeeds (if authentication policy permits such
action).
>
>Also in sec 5.3.2, it says"
>In addition, NHSs that are willing to act as egress routers for
>   packets from the source to the destination SHALL include
information
>   about their NBMA Address".
>
>Please note that the word"NHS" is used throughout and there is no
>mention of a co-existing NHC. Though my personal belief is that
>an "egress NHS" should always be one having both NHS and NHC and
not
>just an NHS, I would like to confirm this assumption.
>
>Regards
>-archana
>
>___________________________________________________________________
_____
>ARCHANA NEHRU                     :  Trillium Digital Systems, Inc
>E-mail: [email-masked]       :  Los Angeles, California
>Phone: +1 310 442 9222
>___________________________________________________________________
_____
>X-Info: To unsubscribe, email [email-masked]' with
>X-Info: 'unsubscribe ion' in the body of the message.
>

X-Info: To unsubscribe, email [email-masked]' with
X-Info: 'unsubscribe ion' in the body of the message.