Subject: Question in Host Address FEC Element encoding

From: "Gangadharan Ramakrishnan" <[email-masked]>
Date: Sun, 22 Jul 2001 19:53:28 +0000

Hi,
I'm following the rfc3036(LDP Specification) for encoding and decoding of 
LDP messages. I found a problem in the specification encoding the Host 
Address FEC Element. The specification says that the PDU filed for Host Addr 
is more than 32 bits in a diagram and it says it is an address encoded 
according to the address family.

I want to know the exact number of bytes/bits for this field. If it is an IP 
address field then there is a typo in the diagram, which represent more that 
32 bits for "Host Addr".

Host Address FEC Element encoding:

0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Host Addr (3) |     Address Family            | Host Addr Len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
|                     Host Addr                                 |
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Host Addr
An address encoded according to the Address Family field.

Thanks,
ganges...

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From: "chetan kumar s" <[email-masked]>
Date: Mon, 23 Jul 2001 19:35:25 +0530 (IST)

> I want to know the exact number of bytes/bits for this field. If it is an IP 

Hi,
As mentioned in the RFC this depends on address family, = 32 for IPv4 and
= 128 for IPv6

Thanks
Chetan S

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From: Eric Gray <[email-masked]>
Date: Mon, 23 Jul 2001 11:25:40 -0400

Chetan S,

    Just to add to this, there may be some unclarity derived from the figure
itself.  It is a convention in ASCII art to represent a _potentially_ multi-word
field using multiple lines, even when the actual field may be one word or less.
The only solution to this inclarity is to become more familiar with ASCII art
in the IETF RFC process...

--
Eric Gray