Re: [nemo] Re: [Mip4] NAT traversal and cellular network administrative filtering

[Alexandru Petrescu <Alexandru.Petrescu at motorola.com>]

Sami Vaarala wrote:
> I'm curious - given the scenario where public addresses are used and 
> IP-IP doesn't work, why does IP-over-UDP work better?

Sorry for intruding here...

It may be the case that operator forbids IP-IP because IP-IP has the
potential to deny the effectiveness of all other firewall filtering
rules that may be in place (rules acting on IP, not IP-in-IP - acting on
IP-in-IP requires more processing time which may be detrimental to
performance).

At the same time, operator may allow certain UDP tunneling to pass
through because that operator may have agreements with Content Providers
that are placed outside that operator's network.  "Content" may be video
streaming over UDP.  So operator assumes that UDP mms port 1755
(Microsoft Multimedia Streaming) should pass through, and keeps it open.

Just a potential explanation, and it's pure speculation, and it may be
far from the actual motivation of T-Mobile filtering rules.

Alex

Attachment: signature.asc
Description: OpenPGP digital signature

-- 
Mip4 mailing list: Mip4 at ietf.org
    Web interface: https://www1.ietf.org/mailman/listinfo/mip4
     Charter page: http://www.ietf.org/html.charters/mip4-charter.html
Supplemental site: http://www.mip4.org/