[rohc] TCP/IP EPIC profile

["Maja" <[e-mail]>]

Hi all,
some points in the latest TCP/IP Header Compression for ROHC (ROHC-TCP) 
draft from January are not clear (OK. Not clear to me ).

First is the definition of the U ( ) method called for TCP options, for example:
 
  tcp-options-co  =    ROTATE(3,1) ; get TCP data offset 
                        LIST(4,1,32,-160,8, 
                           U(OPTIONAL(tcp-sack-co)), 
                           U(OPTIONAL(tcp-timestamp-co)), 
                           U(OPTIONAL(tcp-mss)), 
                           U(OPTIONAL(tcp-end)), 
                           U(OPTIONAL(tcp-wscale)), 
                           U(OPTIONAL(sack-permitted)), 
                           U(OPTIONAL(tcp-generic-co)), 
                           U(OPTIONAL(tcp-generic-co)), 
                           5,8,2,0,3,4) 
 
We couldn't find it in none of the EPIC or ROHC drafts.
And the second point is why is it, in the method LIST, twice included tcp-generic-co ( OR for IR/DYN tcp-generic-dyn).
We suppose that is the method which is called if the value in 8 bits is none of 6 values stated at the end of method, but why twice?
 
Cheers,

Maja & Ivana