lesson 2 Flashcards
1
Q
voip protocol issues
A
- needed new protocol
- ip does not offer sequencing
- tcp has too much overhead due to reliability
- udp has low overhead but does not offer sequencing
- rtp was made for voip traffic
2
Q
rtp
A
- real-time transport protocol
- built on udp
- allows transmission of real time data over ip (audio, video)
- identify type of info carried
- add temporary markers and sequence numbers
- monitor packets
3
Q
rtcp
A
- real-time transport control protocol
- based on periodic transmission of control packets
- makes it possible to convey packet count, delay, loss and jitter
- transmitted at least once every 5 seconds
4
Q
voice protocol requirements
A
- reordering
- time stamping
- multiplexing
- low overhead
- no reliability (overhead)
5
Q
parts of a voice packet
A
- voice payload
- rtp header
- udp header
- ip header
- ethernet header
6
Q
voip signalling and media paths
A
- gatekeeper provides call control
- commonly used protocol is sip
- after setup media is exchanged directly between endpoints using rtp
7
Q
call control steps
A
- call setup
- maintenance
- teardown
8
Q
signalling protocols
A
- session initiation protocol (sip)
- h.323 (packet switched)
- sccp (skinny, old cisco)
- mgcp (media gateway control protocol)
9
Q
core methods of sip
A
- invite
- bye
- register
- cancel
- ack
- options
