The failure detection mechanism to trigger an action within FSG relies on the operational state of the messaging SAP. Such failure detection mechanism is referred as a group monitor.
Group monitor can also be used to detect the state change of the PW. PW state change is reflected in the messaging SAP which in turn triggers the state change of an SRRP instance.
All this is implemented through an oper-group object which is described in the 7450 ESS, 7750 SR, 7950 XRS, and VSR Layer 3 Services Guide: IES and VPRN. All entities that needs to be monitored (messaging SAPs and PWs) are associated with this oper-group object. Finally, an SRRP instance (in case of FSG) or a messaging SAP (in case of PW) is instructed to monitor the entities in the oper-group object. State transitions of objects in a oper-group object trigger state transitions of entities that are monitoring them (messaging SAPs and SRRP instances). State transitions of monitored objects in a oper-group cause the following actions:
With FSG, priorities of SRRP instances are recalculated.
With PW termination on BNG, the operational state of the messaging SAP is changed.
The following is an overview of the CLI syntax showing the principles to create an operational group (oper-group). For command descriptions and full syntax, see the 7450 ESS, 7750 SR, 7950 XRS, and VSR Classic CLI Command Reference Guide and 7450 ESS, 7750 SR, 7950 XRS, and VSR MD-CLI Command Reference Guide.
Create an oper-group.
config>service oper-group <name> [create]Add a SAP to the oper-group.
config>service(ies | vprn)>sub-if>grp-if>sap oper-group <name>Link the state of an oper-group to the SAP. A messaging SAP can monitor the state of a PW.
config>service(ies | vprn)>sub-if>grp-if>sap monitor-oper-group <name>Link the state of an oper-group to the SRRP instance. A state transition of an object in the oper-group (not the state of the oper-group itself) triggers an SRRP priority recalculation. When an object within the oper-group goes down, the SRRP priority is lowered by a priority step. The SRRP priority is adjusted on every state transition of an oper-group member object.
config>service(ies | vprn)>sub-if>grp-if>srrp <srrp-id> monitor-oper-group <name> priority-step [0-253]Add a PW to the oper-group. A messaging SAP monitors the oper-group and assumes the state according to the state of the PW in the oper-group. A standby or a down PW state causes the messaging SAP to assume a down state. Otherwise, the messaging SAP would be in the UP state. In order for the SAP to assume the down state, both RX and TX sides of the PW must be shut down. In other words, a PW in standby mode also must have the local TX disabled by the via the ‛slave’ flag (standby-signaling-slave command in the spoke SDP context). Without the TX disabled, the SAP monitoring the PW does not transition in the down state.
config>service>epipe>spoke-sdp oper-group <name>
A hold timer is provided within the oper-group command to suppress flapping of the monitored object (SAP or pseudowire).
Figure: Pseudowire example shows an example with ESM over pseudowire through a VSM loop.
*A:Dut-C>config>service>epipe# info
----------------------------------------------
endpoint "x" create
standby-signaling-master
exit
sap 1/1/7:1 create
exit
spoke-sdp 1:1 endpoint "x" create
precedence primary
no shutdown
exit
spoke-sdp 2:1 endpoint "x" create
no shutdown
exit
no shutdown
----------------------------------------------
*A:Dut-A>config>service>epipe# info
----------------------------------------------
sap ccag-1.b:11 create
exit
spoke-sdp 2:1 create
standby-signaling-slave
oper-group "1"
no shutdown
exit
no shutdown
----------------------------------------------
*A:Dut-B>config>service>epipe# info
----------------------------------------------
sap ccag-1.b:11 create
exit
spoke-sdp 2:1 create
standby-signaling-slave
oper-group "1"
no shutdown
exit
no shutdown
----------------------------------------------
*A:Dut-A>config>service>ies# info
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redundant-interface "redif11" create
address 10.1.1.2/24 remote-ip 10.1.1.4
spoke-sdp 1:1 create
no shutdown
exit
exit
subscriber-interface "subif_1" create
shutdown
address 10.1.1.2/24 gw-ip-address 10.1.1.100
group-interface "grpif_1_2" create
shutdown
redundant-interface "redif11"
exit
exit
subscriber-interface "subTest" create
address 10.1.1.2/24 gw-ip-address 10.1.1.254
group-interface "grpTest" create
redundant-interface "redif11"
sap ccag-1.a:1 create
exit
sap ccag-1.a:11 create
monitor-oper-group "1"
exit
srrp 11 create
message-path ccag-1.a:11
no shutdown
exit
exit
exit
no shutdown
----------------------------------------------
*A:Dut-B>config>service>ies# info
----------------------------------------------
redundant-interface "redif11" create
address 10.1.1.4/24 remote-ip 10.1.1.2
spoke-sdp 1:1 create
no shutdown
exit
exit
subscriber-interface "subif_1" create
shutdown
address 10.1.1.4/24 gw-ip-address 10.1.1.100
exit
subscriber-interface "subTest" create
address 10.1.1.4/24 gw-ip-address 10.1.1.254
group-interface "grpTest" create
redundant-interface "redif11"
sap ccag-1.a:1 create
exit
sap ccag-1.a:11 create
monitor-oper-group "1"
exit
srrp 11 create
message-path ccag-1.a:11
no shutdown
exit
exit
exit
no shutdown
----------------------------------------------
*A:Dut-B>config>service>ies# show srrp
===============================================================================
SRRP Table
===============================================================================
ID Service Group Interface Admin Oper
-------------------------------------------------------------------------------
11 1 grpTest Up initialize
-------------------------------------------------------------------------------
No. of SRRP Entries: 1
===============================================================================
*A:Dut-A>config>service>ies# show srrp
*A:Dut-A>config>service>ies#
===============================================================================
SRRP Table
===============================================================================
ID Service Group Interface Admin Oper
-------------------------------------------------------------------------------
11 1 grpTest Up master
-------------------------------------------------------------------------------
No. of SRRP Entries: 1
===============================================================================