This command establishes SCTP associations. There can be only a
maximum of three ASPs configured per AS. IP precedence is expressed in the ToS
showipsctpassociationparameters output. The default ToS value is 0.
All of the ASPs in an application server must be removed before an
application serever can be unconfigured.
You can configure the precedence value in IUA in the range of 0 to 7
for a given IP address. Within IUA, the upper three bits representing the IP
precedence in the ToS byte (used in the IP header) is set based on the user
input before passing down the value to SCTP. In turn, SCTP passes the ToS byte
value to IP. The default value is 0 for "normal" IP precedence handling.
asp-name argument specifies the name of this
ASP. Theip-precedence keyword sets the precedence and ToS
remote-ip-address argument specifies the IP
address of the remote end-point (the address of MGC, for example). The
number argument can be any IP precedence bits
in the range 1 to 255.
no form of the command results in precedence
bits not being explicitly set by SCTP.
In the case of a hot-standby Cisco PGW2200 pair, from the gateway
(GW) perspective there is usually one ASP active and another in the INACTIVE
state. The ASP_UP message is used to bring the ASP state on the GW to the
INACTIVE state, followed by the ASPTM message, ASP_ACTIVE to ready the IUA link
for data exchange. (Eventually the QPTM Establish Request message actually
initiates the start of the D channel for the given interface.) In the event
that the GW detects a failure on the active ASP, it can send a NTFY message to
the standby ASP to request that it become active.
An ASP can be viewed as a local representation of an SCTP association
because it specifies a remote endpoint that is in communication with an AS
local endpoint. An ASP is defined for a given AS. For example, the following
configuration defines a remote signaling controller
asp-name at two IP addresses for AS as1. The
remote SCTP port number is 2577:
Router(config-iua)# as as1 10.4.8.69, 10.4.9.69 2477
Router(config-iua)# asp asp1 as as1 10.4.8.68 10.4.9.68 2577
Multiple ASPs can be defined for a single AS for the purpose of
redundancy, but only one ASP can be active. The ASPs are inactive and only
become active after fail-over.
In the Cisco Media Gateway Controller (MGC) solution, a signaling
controller is always the client that initiates the association with a gateway.
During the initiation phase, you can request outbound and inbound stream
numbers, but the gateway only allows a number that is at least one digit higher
than the number of interfaces (T1/E1) allowed for the platform.
The following example specifies the IP precedence level on the
specified IP address. This example uses IP precedence level 7, which is the
maximum level allowed:
Router(config-iua)# asp asp1 as ip-precedence 10.1.2.345 7
The following example specifies the IP address to enable and disable
Router(config-iua)# asp asp1 as sctp-keepalive 10.1.2.34
The following example specifies the keepalive interval in
milliseconds. In this example, the maximum value of 60000 ms is used:
Router(config-iua)# asp asp1 as sctp-keepalive 10.10.10.10 60000
The following example specifies the IP address for the SCTP maximum
association and the maximum association value. In this example, a maximum value
of 20 is used:
Router(config-iua)# asp asp1 as sctp-max-association 10.10.10.10 20
The following example specifies the IP address for the SCTP path
retransmission and the maximum path retransmission value. In this example, a
maximum value of 20 is used:
Router(config-iua)# asp asp1 as sctp-path-retransmissions 10.10.10.10 10
The following example specifies the IP address for SCTP T3 timeout
and specifies the T3 timeout value in milliseconds. In this example, the
maximum value of 60000 is used:
Router(config-iua)# asp asp1 as sctp-t3-timeout 10.10.10.10 60000