[lisp] A question regarding draft-boucadair-lisp-v6-compact-header

["Jose Saldana" <[e-mail]>]

Dear Mohamed and Christian,
 
I have read your draft about a compact header for LISP to avoid MTU issues.
 
However, have you also considered bandwidth savings for small packets as an
additional benefit? I mean, when you use LISP to send small packets between
two locations, the overhead is huge:
 
a) For example, if you are sending an IPv4 TCP ACK (40 bytes), with standard
LISP over IPv6 you need 96 bytes:
 
OH (IPv6): 40 bytes
UDP: 8 bytes
LISP: 8 bytes
IH (IPv4): 20 bytes
TCP: 20 bytes
 
However, if you use the compact header proposed in your draft, you will only
need 72 bytes (if I am right), so you are saving 25% of the bandwidth.
Taking into account that there is a high amount of TCP ACKs, this may
perhaps have an impact.
 
 
b) Or if you are sending an RTP sample with e.g. 20 bytes of payload, using
standard LISP over IPv6, you need 116 bytes:
 
OH (IPv6): 40 bytes
UDP: 8 bytes
LISP: 8 bytes
IH (IPv4): 20 bytes
UDP: 8 bytes
RTP: 12 bytes
Payload: 20 bytes
 
But if you use the compact header, you will only need 88 bytes (24% saving).
 
 
In order to increase these savings, we are currently considering the
possibility of submitting a draft adding header compression with ROHC, and
multiplexing a number of small packets into a single LISP one, if the ITR
has a number of small packets in its buffer. Reducing the number of packets
will reduce the processing in intermediate routers, also reducing e.g.
energy consumption and perhaps some processing delays.
 
 
BR,
 
Jose