User's Manual

Parameter
name
Description Default
value
Boundaries
Register
Max Retry
After a failure to reconnect
with the proxy, the IP
Deskphone increases the
amount of time that it
waits for the next
registration retry attempt.
This value, measured in
seconds, is the maximum
value that the IP
Deskphone waits in
between retry attempts
1800 Min: 600
Max: 1800
SRTP
Secure Real-time Transport Protocol (SRTP) encrypts the Real-time Transport Protocol (RTP)
traffic between two end-points to achieve full security for the media path.
Security Descriptions for the Session Description Protocol (SDESC) (RFC4586) defines a
mechanism to transmit the necessary cryptographic parameters between two end-points.
SRTP is initiated when Secure Real-time Transport Control Protocol (SRTCP) allows both
sides of a conversation to agree on the keys you can use to encrypt or decrypt the messages
that are transmitted.
Media security — SRTP
Secure RTP (SRTP) encrypts the media path between two end-points. After both end-points
agree on the necessary parameters to encrypt and decrypt audio packets, the voice path
between them is established.
SRTP is configured on the IP Deskphone to provide multiple levels of protection.
The following table highlights the two cipher suites that are used and their related
parameters.
Table 35: SRTP properties
Parameter
AES_CM_128_HMAC_
SHA1_80
AES_CM_128_HMAC_SHA1_32
Master key
length
128 bits 128 bits
Master salt
length
112 bits 112 bits
SRTP
SIP Software for Avaya 1100 Series IP Deskphones-Administration November 2012 237