Sip & IPv6 - time for action!

SIP & IPV6 ::
A CALL FOR ACTION.

Olle E. Johansson * oej@edvina.net * Twitter oej
Copyright Edvina AB, Sollentuna, Sweden 2011. All rights reserved.

AGENDA

• Why IPv6 for SIP - the really short version

• Betting on both camps - dual stack deployments

• Using DNS

• IP phones and IPv6 - where are they?

• Where to start?

© Copyright 2011 Edvina AB, Sollentuna, Sweden. All rights reserved.

WHY?

• The global pool of IPv4 addresses is empty

• Soon, the regional pools will be empty too

• Internet growth will either happen behind bars or on IPv6.

• There is no other alternative.


BEHIND BARS, YOU SAID?

• Carriers are building Carrier Class NATs

• Which means that your IPv4 Internet access will be hidden behind
NATs - possibly multiple layers

• NATs add latency, something VoIP does not need.

• NATs add complexy to VoIP solutions, at a cost that customers
does not need.

• You do not want this future for VoIP.

IT’S NOT THE END.
IT’S A BEGINNING

• After the global and regional address pools are empty, there will
still be IPv4 addresses available
• IPv4-based solutions will be around for many, many years.
• The cost for new IPv4 public addresses will go up. A lot.
• IPv6 works and exists, so why not be cheap and migrate?
• Let’s build the Internet SIP Federation on IPv6.
It’s time to move on.


SO WHY DELAY DEPLOYMENT?

• If you integrate IPv6 in all deployments today, your cost will be
lower

• Take it step by step instead of one big overhaul in panic at a later
stage

• You know you will have to do it.


SIP & IPV6

• The SIP 2.0 RFC is written both for IPv4 and IPv6
• IPv6 is a natural part of SIP

• What it did not consider was dual stack deployment

• New RFC about dual stack deployment is coming soon

• Based on this, a reference proﬁle for customers and vendors will
have to be produced.


DUAL STACKS
Where no man boldy has gone before.

WE HAVE HAD DUAL STACKS,
BUT NOT LIKE THIS.

• In the 90’s we had dual stacks - but with different hosts and
services
• TCP/IP and Netware IPX stacks in the same PC was very common.

• IPv4 and IPv6 stacks will in many cases reach the SAME hosts
and services

• This causes new issues in applications and phones


THE DUAL STACK ISSUE

• If a server has two DNS records (IPv4 and IPv6), applications should try
IPv6 ﬁrst

• In many networks, IPv6 is link-only and does not have Internet access

• This causes the application to wait for timeout. In SIP, by default that’s 32
seconds

• After that, the application should try the IPv4 record

• This is not acceptable.


THE SOLUTION

• Applications should open two connections simultaneously

• The ﬁrst one to connect (or respond over UDP) wins the session

• The server simply sees the second message as a retransmit

• The client can drop the second session

• This causes no delays and an acceptable user experience

• This is the way we migrate SIP from IPv4 to IPv6.


USING DNS.
We need help telling others about our preferences.

HELPING OTHERS TO CONTACT YOU

• Use SRV records to indicate your preference

• If you have poor IPv6 connectivity, add IPv6 records as second
priority in SRV - telling the world that you prefer IPv4

• If you have native IPv6 and have IPv4 behind multiple layers of
NATs, do the reverse.

• Servers and clients should support ﬁnding servers with the
same address family as the client in the list of SRV records
and use only those that match the client’s preferences.


TALKING ABOUT PHONES...

• Where are the IPv6 compliant phones?

• As soon as customers require it, they will come

• Customers need a reference proﬁle to refer to

• This applies to softphones, chat clients, ALGs, servers and SIP
trunks.

• The change will have to be market driven.
Drive the market in this direction. Now.

A FEW STARTING POINTS

• Phones should support provisioning over IPv6

• Phones should support DHCPv6 as well as router advertisments

• Phones need to understand both IPv4 and IPv6 uri’s

• Phones should support SRV records with both IPv4 and IPv6 -
ﬁnding servers with the same protocol family as the phone

• This list is not complete. Help us expand and correct it.


IETF WORKS PUTS MIGRATION LOAD
ON NEW PHONES

• Changing installed base will cost too much

• New phones with IPv6 support will have to handle reachability to
the old world

• They will have to ask for support from an application layer
gateway (ALG) to handle media

• Running dual stacks internally will mean a more
complex network with new gateway services.


PRACTICAL ISSUE: LOCATION SERVERS

• Is there a way for a phone to register for both IPv4 and IPv6
connections?

• Does this require two registrations?

• Can SIP proxys select outbound connection based on incoming
connection?

• This needs to be tested, speciﬁed and ﬁxed.


MAKE IT SIMPLE.

• Run your enterprise VoIP network on IPv6. Single stack.

• Use the session border controller or outbound proxy for
gatewaying to the old world.

• Avoid dual stacks on end points

• Keep it simple, stupid. Move to IPv6.


OPEN SOURCE LEADS THE WAY.

• Asterisk, FreeSwitch, OpenSIPS and Kamailio all support IPv6

• They can all gateway between IPv4 and IPv6

• Use these in your labs and migration work

• You are hereby granted a license. Use it.


ACTION PLAN
For the SIP community.

ACTION PLAN.

• Get IPv6: Start with tunnel from a public service
• sixxs.net, tunnelbroker.net

• Get software: Install Asterisk 1.8, Kamailio 3.1 and/or new releases of FreeSwitch
• Get phones: There are phones that support IPv6. SNOM leads the way today.
• Fix DNS: Add IPv6 records to DNS. If possible, add a DNS server on IPv6.
• Learn IPv6: Educate your staff.
• Explore IPv6: Look at DHCPv6, router advertisments, privacy addresses,
subnetting and all the other new stuff. It’s fun.
• Just do it: Integrate IPv6 in every project.


PUSH THE SIP FORUM
IN THE RIGHT DIRECTION.

• So far not much

• The next SIPconnect speciﬁcation will require IPv6 support for
compliance

• Marketing agreement with the IPv6 Forum was made in 2010

• If you are a member, help to push them forward.


THINGS HAVE CHANGED.
- AVOID OLD WORK BY THE IPV6 FORUM.

• Have published requirements for ”IPv6 Ready SIP” certiﬁcation

• This includes serious diversions from the IETF SIP standards and
the SIP forum SIPconnect speciﬁcation

• Does not comply with IETF work on SIP migration to IPv6

• Should be considered deprecated as it doesn’t help the industry
or the customers

• We do not need yet another version of SIP.

WHAT CAN YOU DO?

• Support both IPv6 and IPv6 in the VoIP network

• Start experimenting and get knowledge in-house now.

• Push vendors and Open Source projects in this direction.

• Do not buy any VoIP device in 2011 without proven IPv6 support

• Do not refer to the work by the IPv6 Forum in the SIP area.

• Make IPv6 part of every VoIP project. Now.


SIPV6 IN SHORT

• At this point, there is work needed on dual stack deployment

• Single stack deployment with gateways is easier and can be done today.

• We lack commercial products - phones. Customer demand will make a change
quickly.

• Users lack experience and knowledge to validate vendor claims that products
support IPv6

• It’s time for a change. We need SIP over IPv6. Now.


STAY CONNECTED.
Add IPv6 to your uniﬁed communications platform today.

Join us here:
twitter.com/sipv6
6 edvina.net/sipv6
facebook.com/sipv ts:
Vendor tests at SIPit even
Development discussion: www.sipit.net
list
sip-implementors mailing

Sip & IPv6 - time for action!

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