Cisco Cisco Unified IP Interactive Voice Response (IVR) 8.0(1) Release Note
7-14
Cisco Unified Contact Center Express Solution Reference Network Design
Chapter 7 Bandwidth, Security, and QoS Considerations
CAC and RSVP
QoS Considerations for CAD software
The most important network traffic for quality of service consideration in the CAD software is the voice
streams sent between VoIP requestors and providers. The processes that send and receive these voice
streams have been set to have higher priorities than other processing threads. This helps assure that there
will be no delays in processing these voice streams. However, The voice streams themselves contain no
QoS markings. These markings are stripped off when the voice streams are captured by the VoIP
provider's software. The networking components used to send these data streams (switches, routers,
gateways) should be configured with the appropriate QoS settings to ensure the delivery of these voice
streams to meet the intended QoS requirements.
streams sent between VoIP requestors and providers. The processes that send and receive these voice
streams have been set to have higher priorities than other processing threads. This helps assure that there
will be no delays in processing these voice streams. However, The voice streams themselves contain no
QoS markings. These markings are stripped off when the voice streams are captured by the VoIP
provider's software. The networking components used to send these data streams (switches, routers,
gateways) should be configured with the appropriate QoS settings to ensure the delivery of these voice
streams to meet the intended QoS requirements.
CAC and RSVP
Cisco Unified CM supports Resource-Reservation Protocol (RSVP) between endpoints within a cluster.
RSVP is a protocol used for Call Admission Control (CAC) and is used by the routers in the network to
reserve bandwidth for calls. The bandwidth being controlled is only for the voice streams, call signalling
traffic is not part of CAC.
RSVP is a protocol used for Call Admission Control (CAC) and is used by the routers in the network to
reserve bandwidth for calls. The bandwidth being controlled is only for the voice streams, call signalling
traffic is not part of CAC.
Before RSVP, each Cisco Unified CM cluster maintained its own calculation of how many active calls
were traversing between locations in order to calculate bandwidth usage. If more than one Cisco Unified
CM cluster shared the same link, bandwidth would have to be carved out and dedicated for each cluster,
and this led to inefficient use of available bandwidth. RSVP also enables customers to deploy complex
network topology while Location-based CAC is limited to a hub-and-spoke type of topology.
were traversing between locations in order to calculate bandwidth usage. If more than one Cisco Unified
CM cluster shared the same link, bandwidth would have to be carved out and dedicated for each cluster,
and this led to inefficient use of available bandwidth. RSVP also enables customers to deploy complex
network topology while Location-based CAC is limited to a hub-and-spoke type of topology.
RSVP solves this problem by tracing the path between two RSVP Agents that reside on the same LAN
as the IP Phones. A software MTP or transcoder resource that runs on Cisco IOS routers can be RSVP
Agents. The RSVP Agents are controlled by Cisco Unified CM and are inserted into the media stream
between the two IP phones when a call is made. The RSVP Agent of the originating IP Phone will
traverse the network to the destination IP Phone’s RSVP Agent, and reserve bandwidth. Since the
network routers (and not Cisco Unified CM) are keeping track of bandwidth usage, multiple phone calls
can traverse the same RSVP controlled link even if the calls are controlled by multiple Cisco Unified
CMs.
as the IP Phones. A software MTP or transcoder resource that runs on Cisco IOS routers can be RSVP
Agents. The RSVP Agents are controlled by Cisco Unified CM and are inserted into the media stream
between the two IP phones when a call is made. The RSVP Agent of the originating IP Phone will
traverse the network to the destination IP Phone’s RSVP Agent, and reserve bandwidth. Since the
network routers (and not Cisco Unified CM) are keeping track of bandwidth usage, multiple phone calls
can traverse the same RSVP controlled link even if the calls are controlled by multiple Cisco Unified
CMs.
For more information, see the RSVP chapter in Cisco Unified Communications Solution Reference
Network Design (SRND).
Network Design (SRND).
Cisco Unified CCX selects a call center agent independent of the mechanism, using either RSVP or
Location-based CAC; that is, Cisco Unified CCX routes a call to an available agent even though the
agent phone might not be able to receive the call due to lack of bandwidth. Thus, proper sizing of
bandwidth between sites is very important.
Location-based CAC; that is, Cisco Unified CCX routes a call to an available agent even though the
agent phone might not be able to receive the call due to lack of bandwidth. Thus, proper sizing of
bandwidth between sites is very important.
For any call transfer, there are moments when two calls are active. If any of the active calls traverses
between sites, then CAC is used. Even when the original call is placed on hold during a transfer, that call
still takes up the same amount of bandwidth just like an active call.
between sites, then CAC is used. Even when the original call is placed on hold during a transfer, that call
still takes up the same amount of bandwidth just like an active call.
In
and
, the voice gateway and agents are at a remote site, while the Cisco Unified
CCX server is at a data center site. A call from PSTN reaches the voice gateway at the remote site and
connects to Cisco Unified CCX at the data center. This takes one call bandwidth over the WAN link,
which is represented by the caller stream. Once an agent is available and selected at the remote site,
Cisco Unified CCX transfers the call to the agent.
connects to Cisco Unified CCX at the data center. This takes one call bandwidth over the WAN link,
which is represented by the caller stream. Once an agent is available and selected at the remote site,
Cisco Unified CCX transfers the call to the agent.
1.
This is for Cisco Unified CCX Agent E-mail feature and does not apply to Cisco Agent Desktop Browser edition and IP Phone Agent