For starters i would look at the UDP NAT tunneling mechinism to provide it.

On 03/25/2016 09:16 PM, Tom Henderson wrote:

On 03/25/2016 03:49 PM, Derek Fawcus wrote:
Recently I've been working on middlebox s/w:  Firewalls and NAT.

One thing this has brought home to me is just how unreliable
fragmentation is on the current Internet.  NAT will often
simply break it (such that they can not be reassembled) or
just discard them,  and firewalls are often set up to block them.

As such,  almost every protocol now would seem to need protocol
level segmentation/fragmentation,  rather than depend up IP
level fragmentation.

It struck me that it should be quite simple to extend HIP to
support such.

1) Add a Controls bit which advertises that the sender supports
     segmentation.
2) Define a new parameter,  numbered 1 such that it is first in
     the parameters,  and is critical.
     Within the parameter have a seqno/identifier, offset and
     more segments / final segment bit, possibly also a total
     size field.  Define some simple reassembly rules,  similar
     to those for IP fragments, such that one could reassemble
     a HIP packet larger than 2008 bytes if desired (how big?).
3) Possibly also define a none critical parameter within the
     non signed,  non MACed range which advertises the max size
     packet the sender is willing to reassemble.  In fact I guess
     this might remove the need to use a Controls bit,  since it
     would imply the sender can reassemble.

Then have a rule that once one party has seen the other party
advertise the segmentation capability within the current BEX
session, it is free to make use of segmentation towards that peer.

Thoughts?

DF
Hi Derek, I don't remember the details, but in the early days of HIP, it was 
decided to avoid the burden of supporting fragmentation.  I guess I'd prefer to 
see some evidence that HIP messages are being fragmented in the wild before 
starting a work effort to add support.

- Tom

_______________________________________________
Hipsec mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/hipsec


_______________________________________________
Hipsec mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/hipsec

Reply via email to