Nortel SRG50 Configuration Manual

Also see for BCM50: Installation and maintenance guide Keycode Installation Guide Integration guide Installation and configuration guide Documentation update

Contents

Nortel SRG50 Configuration Manual Manual pdf 39 page image

Chapter 4 CS 1000 considerations 39SRG50 Configuration GuideNetwork Bandwidth Management (NBWM)The SRG interoperates with the Network Bandwidth Management (NBWM) feature in a mannersimilar to Media Gateway (MG) 1000B, though only G.711 and G.729 codecs are supported. Atthe SRG, a Virtual Private Network ID (VPNI) and Zone ID are entered with values defined by themain office configuration (see Bandwidth management configuration: NBWM, ADBWM, andACR on page 40). The VPNI and Zone ID allow the CS 1000 to recognize that H.323 and SIP callsto and from the SRG are from a specific Bandwidth Management zone.NBWM allows bandwidth zones to be configured on a network basis so that codec selection andbandwidth allocation software can identify whether IP telephones or gateways are physicallycollocated (in the same bandwidth zone) even though they are controlled by different call servers.NBWM is used to define the codec selection policy and track bandwidth used for calls thattraverse the WAN (interzone calls) and the LAN (intrazone calls). The bulk of configuration forNBWM is done at the main office.Adaptive Network Bandwidth Management (ADBWM)As with NBWM, only the VPNI and Zone ID are required at the SRG in order to implement heAdaptive Network Bandwidth Management (ADBWM) feature on the SRG (see Bandwidthmanagement configuration: NBWM, ADBWM, and ACR on page 40).ADBWM uses real-time interaction to enhance the performance of Voice over Internet Protocol(VoIP) networks. ADBWM adjusts bandwidth limits and takes corrective action in response toQuality of Service (QoS) feedback. This adjustment occurs dynamically, while calls are inprogress. A call server with ADBWM uses VPNIs and Zone IDs to keep track of the bandwidthbeing used between its own zone and zones belonging to other call servers. If the interzone QoSdegrades below an acceptable level, the available bandwidth is reduced automatically between thetwo zones. When the QoS between the two zones improves, the bandwidth limit is allowed toreturn to normal.Alternative Call Routing (ACR)Configuration for Alternative Call Routing (ACR) at the SRG includes datafilling the VirtualPrivate Network ID (VPNI) and Zone ID required by NBWM and ADBWM. However, additionalconfiguration is required and depends on the type of trunking provisioned at the main office:Attendant service or DID trunks (see Bandwidth management configuration: NBWM, ADBWM,and ACR on page 40).ACR for NBWM allows a station-to-station call (that is, a call that does not use a trunk) tooverflow to traditional routes. Overflow can occur if there is insufficient interzone bandwidthavailable to carry the call, or if the QoS has degraded to unacceptable levels. The feature applies tostation-to-station calls between a branch office and main office as well as from one branch officeto another branch office, provided both stations are registered to the same main office.Network administrators who do not want calls to be blocked, yet have a limited amount ofbandwidth available, can use ACR to overflow calls to conventional trunks (PSTN or Tie/MCDN).ACR allows calls to be routed by overflowing them, trading off the capital cost of WANbandwidth against the incremental cost of overflowed calls.