Subject: [sfc] Some difficulty in using MD-1 as mandatory MD Type

From: [email-masked]
Date: Thu, 20 Aug 2015 12:59:35 +0800

Dear Paul & Uri & all,

  Recently, after reading draft SFC-NSH, I read draft-dc-allocation and 
draft-mobitlity-allocation carefully as well. And here is an issue about 
the mandatory MD-Type defined in these drafts.
 
  We all know that, MD-Type=1 is mandatory according to the definition in 
SFC-NSH. And draft-dc and draft-mobility are proposed to define the 
recommended Mandatory Context Headers when MD-Type=1.
 
  We also can know that, it is correct to define differentiated Mandatory 
Context headers format with totally differentiated meaning under 
differentiated scenario. Such as, in a dc scenario, SFs can analyze the 
exactly meanings in the  Mandatory Context headers according to the 
definition in draft-dc, and so is the same in mobility scenario. 

  But, what if in environments with mixed need, such as Data Centers 
providing both wireless and classic DC services. How the SFs in this mixed 
environments to correctly analyze the Mandatory Context headers in the NSH 
when the MD-Type is set 1 ? In other words, how the SFs in this mixed 
environments know the receiving Mandatory Context headers in the NSH are 
used for wireless service or classic DC services?

  Hope I express my question clearly and expect reply:) Thanks very much:)

Best Wishes,
Linda Wang