Cisco 7841 Administration Guide

Control SIP and RTP Behaviour in Dual Mode
You can control SIP and RTP parameters with SIP IP Preference and SDP IP Preference fields when phone
is in dual mode.
SIP IP Preference parameter defines which IP address phone tries first when it is in dual mode.
Table 12: SIP IP Preference and IP Mode
Failover SequenceAddress List from DNS, Priority, Result
P1 - First Priority Address
P2 - Second Priority Address
SIP IP
Preference
IP Mode
1.1.1.1 ->2009:1:1:1:1 ->
2.2.2.2 -> 2009:2:2:2:2
P1- 1.1.1.1, 2009:1:1:1::1
P2 - 2.2.2.2, 2009:2:2:2::2
Result: Phone will send the SIP messages to 1.1.1.1
first.
IPv4Dual
Mode
2009:1:1:1:1 ->
1.1.1.1 -> 2009:2:2:2:2 ->
2.2.2.2
P1- 1.1.1.1, 2009:1:1:1::1
P2 - 2.2.2.2, 2009:2:2:2::2
Result: Phone will send the SIP messages to
2009:1:1:1::1 first.
IPv6Dual
Mode
2009:1:1:1:1 -> 2.2.2.2 ->
2009:2:2:2:2
P1- 2009:1:1:1::1
P2 - 2.2.2.2, 2009:2:2:2::2
Result: Phone will send the SIP messages to
2009:1:1:1::1 first.
IPv4Dual
Mode
2009:1:1:1:1 -> 2009:2:2:2:2
->2.2.2.2
P1- 2009:1:1:1::1
P2 - 2.2.2.2, 2009:2:2:2::2
Result: Phone will send the SIP messages to 1.1.1.1
first.
IPv6Dual
Mode
1.1.1.1 -> 2.2.2.2P1 - 1.1.1.1, 2009:1:1:1::1
P2 - 2.2.2.2, 2009:2:2:2::2
Result: Phone will send the SIP messages to 1.1.1.1
first.
IPv4
or
IPv6
IPv4
Only
2009:1:1:1:1 ->
2009:2:2:2::2
P1 - 1.1.1.1, 2009:1:1:1::1
P2 - 2.2.2.2, 2009:2:2:2::2
Result: Phone will send the SIP messages to
2009:1:1:1::1 first.
IPv4
or
IPv6
IPv6
Only
SDP IP Preference - ALTC helps peers in dual-mode negotiate RTP address family.
Cisco IP Phone 7800 Series Multiplatform Phones Administration Guide
57
Cisco IP Phone Installation
Control SIP and RTP Behaviour in Dual Mode

Cisco 7841 Specifications

General

Ethernet Switch	Yes
Lines	4
Headset Port	Yes
Wall Mountable	Yes
Display	3.5-inch grayscale display
Audio	Wideband audio
PoE	IEEE 802.3af
Speakerphone	Full-duplex
Ethernet Ports	2 x 10/100/1000
Headset Jack	RJ9
Protocols	SIP
Codec Support	G.711, G.722, G.729, iLBC
Mounting	Desk or wall
Weight	1 kg