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The SBC supports TCP (Transmission Control Protocol) for peering, enterprise, and access configurations.
In an Access scenario, connections are on a per-subscriber-registration basis. The SBC keeps track of subscriber-initiated TCP “flow” beginning with when the endpoint registers, and uses it to forward any requests to the subscriber. The connection stays up as long as the subscriber is registered with SBC.
A connection is deleted when the flow cannot reach the subscriber (example a broken TCP connection), when the connection is replaced by a newer one through successful modification, or when the registration is deleted.
For Peering, there are typically two connections, one for each direction. Connections to the peers are maintained and reused for all requests to the peer, independent of calls. The SBC can accept multiple connections from the same remote peer.
The SBC also supports TCP Fallback. When enabled, the following functionality is available:
When TCP fallback feature is enabled it overrides any other configuration related to transport preference.
When a UE sends REGISTER request to the SBC over a TCP connection and the registration is successful, the TCP connection is present between UE and SBC for the life of the registration. If the registration becomes inactive, the SBC relies on the UE to clear (close) the TCP connection between the two.
The SIP Trunk Group flag clearTcpConnectionsforRegistration
allows the SBC to clear the TCP connection between UE and SBC once the registration becomes inactive. The SBC closes the TCP connection even when there are user agent failure registrations.
The
The following example sets the NAT keep-alive timer to 200 seconds for SIP over TCP.
% set addressContext default zone ZONE_IAD sipTrunkGroup SBX10_IAD services natTraversal tcpKeepaliveTimer 200 % commit % show addressContext default zone ZONE_IAD sipTrunkGroup SBX10_IAD services natTraversal { tcpKeepaliveTimer 200; }
For configuration details, see SIP Trunk Group - Services (EMA) or SIP Trunk Group - Services - CLI.
The following example sets tcpKeepaliveTime
to 90 seconds, tcpKeepaliveInterval
to 60 seconds and tcpKeepaliveProbes
count to 2 for SIP Signaling Port 2:
% set addressContext default zone ZONE_SIPART_AS sipSigPort 2 tcpKeepaliveTime 90 tcpKeepaliveInterval 60 tcpKeepaliveProbes 2 % commit % show details addressContext default zone ZONE_SIPART_AS sipSigPort 2 ipInterfaceGroupName LIG2; ipAddressV4 10.7.14.179; portNumber 5060; mode inService; state enabled; recorder disabled; siprec disabled; tcpConnectTimeout 5; dscpValue 0; tlsProfileName defaultTlsProfile; transportProtocolsAllowed sip-tcp; sctpProfileName defaultSctpProfile; tcpKeepaliveTime 90; tcpKeepaliveInterval 60; tcpKeepaliveProbes 2;
For configuration details, see Signaling Ports - Sip Sig Port (EMA) or Zone - SIP Sig Port - CLI.
The
The two configurable fields/parameters under tcpPortRange
include:
baseServerPort
– The starting (base) port number for the range of TCP ports to use for media. The baseServerPort
range is 1-65534, or "none" (the default value which indicates SBC does not apply this SIP trunk group control, and instead uses the tcpPortRange specified by system-wide settings.maxServerPort
– The maximum TCP port number for the range of TCP ports to use for media. This value must be greater than the baseServerPort
. The maxServerPort
range is 1-65534, or "none" (the default value which indicates SBC does not apply this SIP trunk group control, and instead uses the tcpPortRange specified by system-wide settings.Each SIP trunk group can include a mediaIpAddress
to indicate which IP address to use when allocating TCP media. The default value is 0.0.0.0 indicating that the system will function as it currently does by choosing an IP Address from the mediaIpInterfaceGroup
. The mediaIpAddress
can be configured as either an IPv4 or IPv6 address. Any media IP address configured must belong to the IP Interface Group configured as the mediaIpInterfaceGroup
for the trunk group.
Use the CLI 'show table' command to view the ipInterfaceGroup
table listing TCP (or UDP) port ranges marked (mediaPortRangeAssigned
) or unmarked (mediaPortRangeUnassigned
) for the indicated IP Interface Group.
For configuration details, see: