www.gentrice.net

v4/v6 dual stack voip network planning

case study : TANET VOIP 交換平台

顯赫資訊Kaiser

www.gentrice.net

教育部交換平台

• 教育部自編門號• 超過千所學校互連• 封閉型編碼• 標準 sip 協定

www.gentrice.net

Voip numbering• 9xx-yyyyy

– 9xx, 單位 (14 區網， 25 縣市網）– V4 only now

www.gentrice.net

IP v4/v6 issue in voip service

• IP v4/v6 in– UA (IP-Phone, GW, softphone…. )

– Proxy server

– IP-PBX (B2BUA)

– Application (ex: MCU, enum…)

• We can not replace all IPv4 SIP device over night– UA (CPE) support dual stack

– SIP server support dual stack

• Heavy loading– in sip for sip translation between 4/6.

www.gentrice.net

VoIP IPv6

• CPE– Dual stack?– Dual UA ?

• Server– V6 in a single thread

• V4 voip is stable now

– V4 + V6 dual transport

• B2BUA Translation– RTP header rewrite – No P2P

• GW– None in market

www.gentrice.net

SIP server

• Call type– V4<-->V4– V4<-->V6– V6<-->V6

• Translation– Signaling , need to be done in B2BUA – RTP

• V6 logo • Enum

www.gentrice.net

Test items

www.gentrice.net

SIP Message

• Application layer• SIP is plain text• Broken V4 UA

– Host:port 192.168.0.100:5060

– v6 addr fe80::219:e3ff:fe05:42a0

www.gentrice.net

Peer to Peer VoIP

• IPv4– Nat issue

• IPv6– V6 to V6, no problem (expect B2BUA)

– V4 to V6

– V6 to V4

www.gentrice.net

302 move temporary

• 有效降低 v4/v6 上的 voip 轉換– 話機需能支援 302 後的 new invite

– Server 需能判斷話機是否支援 dual stack

www.gentrice.net

302 call flow

45670(dual stack)

RTP Stream(IPv4)

PROXY(dual stack)

45674(IPv4 only)

1.INVITE(IPv6)

5.INVITE(IPv4)

6.200 OK(IPv4)7.200 OK(IPv4)

8.ACK(IPv4) 9.ACK(IPv4)

2.302 Move Temporarily (IPv6)

4.INVITE(IPv4)

3.200 OK(IPv6)

Source: 台南市教育局

www.gentrice.net

www.gentrice.net

Case study

• 雲林縣– All ip-phone in v6 network, now over 1000+ phone – PSTN GW still in v4– 桃園、澎湖 follow v6 only in ipphone

• 台南– V6 in new phone number block– V6 call first, v4 failfall

• 北縣– V4 major, V6 in selected phone

www.gentrice.net

V6 IP-Phone

• Too many v4 only NAT box in campus– IP-PHONE 跑 v6 造成困難

• Core switch/ L2/ L3 switch• TANET release more v4 IP to reduce NAT

environment.

www.gentrice.net

結論

• V6 可有效加速 voip deployment

• 日本企業網路優先配發 v6

• dual stack 是未來趨勢– 如果降低 v4/v6 轉換 是未來 service provider

需考量的一環– 新的相關參數的制定– 台灣經驗