Subject: [sfc] #20 (architecture): Word size limitation with MDType 1

From: "sfc issue tracker" <[email-masked]>
Date: Wed, 04 May 2016 15:57:53 -0000

#20: Word size limitation with MDType 1

 Two points are being raised wrt MDType1 in NSH (document: draft-ietf-sfc-
 nsh-04.txt):

 (a) The fixed size and length of MDType1 issue was raised in email group
 by few folks which is yet to be  addressed.
 The issue of MDType1 size arbitrarily being fixed 4 words is questionable
 as in many use cases and implementations.
 Also it is inefficient in the cases where less than 4 words suffices.
 Rather having one MDType (type 2) would suffice and address most if not
 all cases.
 The argument of MDTyp1 and being fixed 4 words for hardware efficiency
 need to be thought through.
 In above cases since it actually hinders overall system to process
 (reads/writes) the words (zeros in Context header) not in use for each
 packet for ingress and egress. For cases requiring more than 4 words,
 MDType2 would be the solution anyway but in this case each packet is
 mandated to still have MDType1 and of fixed 4 words of zeros for ingress
 and egress.

 (b) There is open ticket request to allocate flags in header for MDType to
 specify: append only, rw, mimic flags for nodes in transit to
 modify/update/preserve Metadata along the path.

-- 
-----------------------------+------------------------
 Reporter:  [email-masked]   |      Owner:  Paul Quinn
     Type:  defect           |     Status:  new
 Priority:  major            |  Milestone:  milestone1
Component:  architecture     |    Version:  2.0
 Severity:  In WG Last Call  |   Keywords:  NSH
-----------------------------+------------------------

Ticket URL: <https://trac.tools.ietf.org/wg/sfc/trac/ticket/20>
sfc <https://tools.ietf.org/sfc/>

---

From: "sfc issue tracker" <[email-masked]>
Date: Wed, 04 May 2016 16:02:28 -0000

#20: Context Header size limit with MDType 1

-- 
-----------------------------+-------------------------
 Reporter:  [email-masked]   |       Owner:  Paul Quinn
     Type:  defect           |      Status:  new
 Priority:  major            |   Milestone:  milestone1
Component:  architecture     |     Version:  2.0
 Severity:  In WG Last Call  |  Resolution:
 Keywords:  NSH              |
-----------------------------+-------------------------

Ticket URL: <https://trac.tools.ietf.org/wg/sfc/trac/ticket/20#comment:1>
sfc <https://tools.ietf.org/sfc/>