Subject: [mpls] Return path spesified LSP Ping draft - required updates

From: "Ehud Doron" <[email-masked]>
Date: Mon, 12 Jul 2010 18:09:38 +0300

Hi Mach

Kindly we would like to suggest the following enhancements for the
Return path specified LSP Ping next draft.

1.       Reply Path (RP) Return Code

Following our last discussions please find attached our suggestions for
RP Return Code.

The RP return code shall be part of RP TLV. The RP TLV shall have the
following structure:

0                              7  8                                15 16
23 24                            31

RP return code

RP return sub-code

RP sub-TLVs

The Reply Path Return Code it a dedicated return code for RP operations
(separated from the forward return code  in Echo Reply header). It used
by the forward LSP Tail End to report the forward LSP Head End about the
actions he took while selecting the RP. The forward LSP Tail End can set
it to one of the values listed below. The RP Return Subcode must be set
to zero.

  Value Meaning

----------------------

0 - No return code

1 - Malformed RP TLV was received

2 - One or more of the sub-TLVs in RP TLV was not understood

3 - The echo reply was sent successfully using the specified RP 

4 - The specified RP was not found, the echo reply was sent via other
LSP

5 - The specified RP was not found, the echo reply was sent via IP path

6 - The Reply mode in echo request was not set to 5 (replay via
specified path) although RP TLV exists

7 - RP TLV was missing in echo reply

Examples of usage of this return code:

If the RP TLV contains IPv4 RSVP-TE tunnel sub-TLV and the flag fields
are P=1 S=1, it is required to set the RP Return Code to 2 , "One or
more of the sub-TLVs in RP TLV was not understood". Here it is required
to use the default return path.

If the Reply Mode field in the received echo request is equal to "Reply
via specified path" and no RP TLV exists in the echo request, it is
required to set the RP Return Code to "RP TLV was missing in echo
reply". Here it is required to use the default return path.

2.       New sub-TLV for RP EXP 

In addition, we conclude that it is required to add new sub-TLV to RP
TLV  the RP EXP sub-TLV. This TLV is used by the originator of the echo
request to specify the echo reply sender which EXP bits to use while
sending the echo reply in the specified LSP. This TLV is similar in its
sense to Reply TOS Byte TLV for IP reply path (as defined in RFC4379).

RP EXP sub-TLV structure:

0              2              7  8                                15 16
23 24                            31

RP EXP bit

Must be Zero

We think that this sub-TLV is essential and must be added. 

Please refer

Ehud    Doron

System Architect 

Orckit - Corrigent

[email-masked] <mailto:[email-masked]>    

Tel: 972-3-69456327

www.orckit.com <http://www.orckit.com/>  

  <http://www.orckit.com/> 

Pushing technology to the edge

---

From: Mach Chen <[email-masked]>
Date: Tue, 13 Jul 2010 16:12:25 +0800

Hi Ehud,

Thanks for your detailed suggestions! We will consider the suggestion and 
try to incorporate them into the next revision.

Best regards,
Mach

--------------------------------------------------
From: "Ehud Doron" <[email-masked]>
Sent: Monday, July 12, 2010 11:09 PM
To: "Mach Chen" <[email-masked]>
Cc: "Yossi Fridman" <[email-masked]>; "Ehud Doron" <[email-masked]>; 
"Rafi Ram" <[email-masked]>; "Nir Ben Avraham" <[email-masked]>; "Ofer 
Dayan" <[email-masked]>; <[email-masked]>; "Ronen Solomon" 
<[email-masked]>; "Shai Bromberg" <[email-masked]>
Subject: Return path spesified LSP Ping draft  - required updates