All Flashcards
What does MGCP use specifying and negotiating the media streams.
Session Description Protocol (SDP)
What port does MGCP leverage for control traffic?
UDP port 2427
What port does MGCP leverage for backhaul traffic?
TCP port 2428
What MGCP Call State command is sent from a call-control agent to an MGCP-controlled gateway for creating a new connection between two MGCP endpoints?
CreateConnection (CRCX)
What MGCP Call State command is sent from a call-control agent to an MGCP-controlled gateway that modifies the parameters associated with an existing connection?
ModifyConnection (MDCX)
What MGCP Call State command is bidirectional and used by a call-control agent to inform the gateway that it should terminate a connection and is also used by a Gateway to indicate that a connection needs to be terminated?
DeleteConnection (DLCX)
What MGCP Call State command is bidirectional and sends statistics associated with the connection when contacting the call-control agent?
DeleteConnection (DLCX)
What MGCP Call State command is sent from a call-control agent to an MGCP-controlled gateway that configures the gateway with bearer information, which specifies whether audio calls will be encoded using mu-law or A-law?
EndpointConfiguration (EPCF)
What MGCP Call State command is sent from a call-control agent to an MGCP-controlled gateway to instruct the gateway to inform the call-control agent when specific events such as on-hook/off-hook actions or DTMF tones occur on a specified endpoint?
NotificationRequest (RQNT)
What MGCP Call State command is sent from a call-control agent to an MGCP-controlled gateway to audit the status of an endpoint (port), such as bearer information, signal status, and event status?
AuditEnpoint (AUEP)
What MGCP Call State command is sent from a call-control agent to an MGCP-controlled gateway to discover the status of a connection, such as connection mode, call ID, and connection parameters?
AuditConnection (AUCX)
What MGCP Call State command is sent from an MGCP-controlled gateway to a call-control agent to inform the call-control agent when requested events occur such as on-hook/off-hook and digit reception?
Notify (NTFY)
What MGCP Call State command is sent from an MGCP-controlled gateway to a call-control agent to inform the call-control agent that the gateway is taking an endpoint or group of endpoints out of service or returning an endpoint or group of endpoints to service?
RestartInProgress (RSIP)
What are three types of MGCP Restarts?
- Restart (endpoint in service)
- Graceful (wait until call clearing)
- Forced (endpoint out of service)
What is the MGCP return code for Response Acknowledgement Messages as defined by RFC 3661?
000
What is the MGCP return code for Transactional Execution-related Messages as defined by RFC 3661?
1XX
What is the MGCP return code for Transactional Successful Messages as defined by RFC 3661?
2XX
What is the MGCP return code for Transient Error Messages as defined by RFC 3661?
4XX
What is the MGCP return code for Permanent Error Messages as defined by RFC 3661?
5XX
What are the various MGCP return codes as defined by RFC 3661 and what do they mean?
000: Response acknowledgement message 1XX: Transaction execution-related messages 2XX: Transaction successful messages 4XX: Transient error messages 5XX: Permanent error messages
What port does MGCP use to send messages?
UDP port 2427
What port does MGCP use to exchange keep-alive packets between an MGCP-controlled gateway and CUCM?
TCP port 2428
What MGCP command enables graceful switchback from one CUCM server to another in case of a CUCM server failure and what are the options?
ccm-manager switchback
graceful immediate never schedule-time uptime-delay
What are the 3 different categories of QoS and how strict is each?
IntServ - Strict
DiffServe - Less strict
Best Effort - Not strict
What is are 5 common QoS mechanisms?
- Classification and Marking
- Queuing
- Congestion Avoidance (RED or WRED)
- Policing and Shaping
- Link Efficiency
What is the difference between shaping and policing?
Policing is more strict. If traffic exceeds more than the specified bandwidth then it is often dropped. In the case of TCP traffic, it will be retransmitted.
Shaping is less strict. If traffic exceeds more than the specified bandwidth (CIR) then it is queued and sent as soon as bandwidth is available.
What are two common Link Efficiency mechanisms?
- RTP Header Compression (cRTP)
2. Link Fragmentation and Interleaving (LFI)
What is the size of a standard RTP Header?
40 Bytes
What are the two potential sizes of a compressed RTP Header and what do most systems default to?
2 Bytes (without UDP Checksum) 4 Bytes (with UDP Checksum)
What is the bandwidth amount where it makes sense to use LFI?
Less than 768 Kbps
If you have 768 Kbps or higher then do not use LFI.
What is the command to enable auto QoS for voice on a Cisco router running Frame-Relay?
Int serial 0/0/0.101
frame-relay interface-dlci 101
auto qos voip
What is the difference between using the “auto qos voip” command or the “auto qos voip trust” command on a Cisco router?
auto qos voip will use NBAR to identify well known traffic types.
auto qos voip trust will trust the already existing DSCP markings.
What port does the SIP protocol use?
TCP or UDP 5060
What port does the Secure SIP protocol use and what does it use for signaling?
Known as Secure SIP (SIPS). It uses TLS for signaling and operates on TCP port 5061.