Factors that effectthe real-time capacity 115
Fax traffic is alwaysone-way. Fax pages sent and fax pages received
generate data traffic to the TLAN subnet. For WAN calculation, only the
larger traffic parcel of the two must be considered.
Trunk Anti-Tromboning(TAT) and TrunkRoute Optimization (TRO)considerations
TrunkAnti-Tromboning (TAT)was designed to remove tromboning trunks
after a call was answeredby a third party. Anti-Tromboning can occur in the
following scenarios.
•If a call is re-directed due to call forward or hunt,tr unks are torn down
after the third party answers.
•Tromboningtrunks are removed due to call modification, such as
transfer or conference,after the third party answers the call and the call
modification is completed.
•For calls entering the private network on CO trunks, the privatenetwork
trunks being tromboned due to call modification or call redirection are
removed.
The removal of trunks in the previous scenarios frees resources that would
be otherwise tied up due to tromboning. Therefore, a customer can reduce
the call blocking caused by excessivetrunk tromboning. This feature works
in a PRI, ISL, and VNS network.
TATenhancement
IP Trunk3.01(and later) introduces an improved TATvalidation check
that greatly reduces the number of valid anti-tromboning cases for which
TAT is blocked. The check works by comparing the H.323 Gateway
Endpoint ID (EPID) that allows TAT to optimize trunk connections in all valid
anti-tromboning cases. The EPID is the MAC address of an H.323 Gateway
host, such as an IP Trunkcard or Signaling Server.
As a fallback TAT validation mechanism, IP Trunk3.01 (and later) uses the
IP Trunk3.01 validation check of comparing called and calling numbers. IP
Peer in CS 1000 Release 2.0, IP Trunk3.01, BCM 3.0.1, and BCM 3.5 do
not support the new TATvalidation check comparing EPIDs. Therefore,
when interoperating with these systems, IP Trunk3.01 (and later) falls back
to the IP Trunk3.01 (and later) TAT validation mechanism of comparing
called and calling numbers. This results in the blocking of the TAT operation
in severalvalid anti-tromboning cases, as previously discussed.
When tromboning of IP Trunksoccurs due to limited TAToperation with CS
1000 Release 2.0 and BCM 3.5, BCM and IP Peer use H.245 signaling to
the IP Trunk3.01 (and later) node to establish a direct media path between
Nortel Communication Server 1000
IP TrunkFundamentals
NN43001-563 02.01 Standard
Release 5.5 21December 2007
Copyright© 2007, Nor tel Networks
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