The 7450ESS, 7750SR, and 7950XRS support both the virtual channel and non-virtual channel for sub-ring control communication. In the virtual channel mode, a dedicated VID, other than the major ring RAPs control channel is configured as a data instance on the major ring. This allows the sub-ring control messages and state machine logic to behave similar to a major ring. In the non-virtual channel mode, the sub-ring is only connected by the RAPs control channels on the sub-ring itself. This mode offers slightly less redundancy in the RAPs messaging than the virtual channel mode because sub-ring RAPs messages are not propagated across the major ring. When non-virtual link is configured, the protocol allows RPL messages over the sub-ring blocked link.
Sub-ring configuration is similar to major ring configuration and consists of three parts: Ethernet-ring instance configuration, control VPLS configuration, and data VPLS configuration (data instance or data channel). The Ethernet-ring configuration of a sub-ring is tied to a major ring and only one path is allowed.
Note: A split horizon group is mandatory to ensure that Sub-Ring control messages from the major ring are only passed to the sub-ring control.
As with a major ring, the forwarding of CCMs and G.8032 R-APS messages continues in the control VPLS even if the service or its SAPs are administratively shut down. The Ethernet ring instance can be shut down if it is needed to stop the operation of the ring on a node.
The data VPLS can be configured on the major ring, and in the example, shares the same VID (SAP encapsulation) on both the major ring and the sub-ring to keep data on the same VLAN ID everywhere.
Note: Similar to other services in the router, the SAP configuration controls the encapsulation VID and the Ring ID of the Ethernet ring controls the association to the controlling ring.
The following example shows a sub-ring configuration.
Sub-ring configuration using a virtual link (MD-CLI)
[ex:/configure eth-ring 2]A:admin@node-2# info admin-state enable description "Ethernet Sub Ring on Ring 1" sub-ring { description "Using a virtual link" type virtual-link interconnect { ring-id 1 propagate-topology-change true } } path "a" { admin-state enable description "Ring control uses VID 100" port-and-raps-tag 1/1/3:100 eth-cfm { mep admin-state enable ccm true control-mep ma-admin-name "4" md-admin-name "1" mep-id 9 } }Sub-ring configuration using a virtual link (classic CLI)
A:node-2>config>eth-ring# info---------------------------------------------- description "Ethernet Sub Ring on Ring 1" sub-ring virtual-link interconnect ring-id 1 propagate-topology-change exit exit path a 1/1/3 raps-tag 100 // Ring control uses VID 100 eth-cfm mep 9 domain 1 association 4 ccm-enable control-mep no shutdown exit exit no shutdown exit no shutdown exitIf you configure the sub-ring as a non-virtual link, the previous sub-ring configuration and on all the other sub-ring nodes for the sub-ring are as shown in the following example. The control channel for the major ring ERP1 illustrates that the major ring control is separate from the sub-ring control.
Sub-ring configuration using a non-virtual link (MD-CLI)
[ex:/configure service]A:admin@node-2# info vpls "10" { admin-state enable description "stadmin=" customer "1" stp { admin-state disable } sap 1/1/1:10 { eth-ring 1 stp { admin-state disable } } sap 1/1/4:10 { eth-ring 1 stp { admin-state disable } } }Sub-ring configuration using a non-virtual link (classic CLI)
A:node-2>config>service# info---------------------------------------------- vpls 10 customer 1 create description "stadmin=" stp shutdown sap 1/1/1:10 eth-ring 1 create stp shutdown exit sap 1/1/4:10 eth-ring 1 create stp shutdown exit no shutdown exit Data configuration for the non-virtual Sub-Ring (MD-CLI)
[ex:/configure service]A:admin@node-2# info vpls "11" { admin-state enable description "Data on VID 11 for Ring 1" customer "1" stp { admin-state disable } sap 1/1/1:11 { description "VID 11 used for ring" eth-ring 1 stp { admin-state disable } } sap 1/1/4:11 { eth-ring 1 stp { admin-state disable } } sap 1/1/3:11 { description "Sub-ring data" eth-ring 2 stp { admin-state disable } } sap 3/2/1:1 { description "Local Data SAP" stp { admin-state disable } } }Data configuration for the non-virtual Sub-Ring (classic CLI)
A:node-2>config>service# info---------------------------------------------- vpls 11 customer 1 create description "Data on VID 11 for Ring 1" stp shutdown sap 1/1/1:11 eth-ring 1 create // VID 11 used for ring stp shutdown exit sap 1/1/4:11 eth-ring 1 create stp shutdown exit sap 1/1/3:11 eth-ring 2 create // Sub-ring data stp shutdown exit sap 3/2/1:1 create description "Local Data SAP" stp shutdown no shutdown exitYou could configure a control channel for the sub-ring using a virtual link. This is a data channel as far as the ring 1 configuration. Other ring 1 nodes also need this VID to be configured.
Control channel for the sub-ring using a virtual link (MD-CLI)
[ex:/configure service]A:admin@node-2# info vpls "100" { admin-state enable description "Control VID 100 for Ring 2 Interconnection" customer "1" split-horizon-group "s1" description "Ring split horizon group" stp { admin-state disable } sap 1/1/1:100 { split-horizon-group "s1" eth-ring 1 stp { admin-state disable } } sap 1/1/4:100 { split-horizon-group "s1" eth-ring 1 stp { admin-state disable } } sap 1/1/3:100 { eth-ring 2 stp { admin-state disable } } }Control channel for the sub-ring using a virtual link (classic CLI)
A:node-2>config>service# info---------------------------------------------- vpls 100 customer 1 create description "Control VID 100 for Ring 2 Interconnection" split-horizon-group "s1" create //Ring split horizon Group exit stp shutdown sap 1/1/1:100 split-horizon-group "s1" eth-ring 1 create stp shutdown exit sap 1/1/4:100 split-horizon-group "s1" eth-ring 1 create stp shutdown exit sap 1/1/3:100 eth-ring 2 create stp shutdown exit no shutdown exit If you configure the sub-ring as a non-virtual-link, the previous configuration would be like the following example.
Control channel for the sub-ring using a non-virtual link (MD-CLI)
[ex:/configure service]A:admin@node-2# info vpls "100" { admin-state enable description "Control VID 100 for Ring 2 Interconnection" customer "1" sap 1/1/3:100 { eth-ring 2 stp { admin-state disable } } } Control channel for the sub-ring using a non-virtual link (classic CLI)
A:node-2>config>service# info----------------------------------------------vpls 100 customer 1 create description "Control VID 100 for Ring 2 Interconnection" sap 1/1/3:100 eth-ring 2 create stp shutdown exit no shutdown exit The 7450ESS, 7750SR, and 7950XRS allow for a special configuration of the non-virtual link sub-ring that can behomed to a VPLS service illustrated in 0-6 sub-ring homed to VPLS. Thisis an economical way to have a redundant ring connection to a VPLS service. This iscurrently supported only for dot1Q and QinQ sub-rings and only on LDP based VPLS.The primary application for this is access rings that require resiliency. Thisconfiguration shows the configuration for a sub-ring at an interconnection nodewithout a virtual channel and interconnected to a VPLS. A VPLS service 1 is used toterminate the ring control. The Ethernet ring data SAP appears in the associated LDPbased VPLS service 5.
The following example is a sub-ring configuration for VPLS (at PE1 in 0-7 multi ring hierarchy).
Sub-ring configuration for a VPLS (MD-CLI)
[ex:/configure eth-ring 1]A:admin@node-2# info description "Eternet_Ring_1" guard-time 20 revert-time 0 rpl-node neighbor sub-ring { interconnect { vpls propagate-topology-change true } } path "a" { admin-state enable description "Ethernet Ring : 1 Path on LAG" port-and-raps-tag 1/1/3 eth-cfm { mep admin-state enable ccm true control-mep ma-admin-name "8" md-admin-name "1" mep-id 8 } }Sub-ring configuration for a VPLS (classic CLI)
A:node-2>config>eth-ring# info---------------------------------------------- description "Ethernet Ring 1" guard-time 20 no revert-time rpl-node nbr sub-ring non-virtual-link interconnect vpls propagate-topology-change exit exit path a 1/1/3 raps-tag 1.1 description "Ethernet Ring : 1 Path on LAG" eth-cfm mep 8 domain 1 association 8 ccm-enable control-mep no shutdown exit exit no shutdown exit no shutdownexitConfiguration for the VPLS ring-control interconnection termination (MD-CLI)
[ex:/configure service]A:admin@node-2# info vpls "1" { admin-state enable description "Ring 1 control interconnection termination" customer "1" sap 1/1/3:1.1 { description "path a control" eth-ring 1 stp { admin-state disable } } } Configuration for the VPLS ring-control interconnection termination (classic CLI)
A:node-2>config>service# info---------------------------------------------- vpls 1 customer 1 create description "Ring 1 control interconnection termination" stp shutdown sap 1/1/3:1.1 eth-ring 1 create //path a control stp shutdown exit no shutdown exitConfiguration for the ring data into an LDP-based VPLS (MD-CLI)
[ex:/configure service]A:admin@node-2# info vpls "5" { admin-state enable description "VPLS Service at PE1" customer "1" mesh-sdp 5001:5 { description "sample LDP MPLS LSPs" } mesh-sdp 5005:5 { } mesh-sdp 5006:5 { } sap 1/1/3:2.2 { eth-ring 1 stp { admin-state disable } sap 1/1/5:1 { } }Configuration for the ring data into an LDP-based VPLS (classic CLI)
A:node-2>config>service# info---------------------------------------------- vpls 5 customer 1 create description "VPLS Service at PE1" stp no shutdown exit sap 1/1/3:2.2 eth-ring 1 create stp shutdown exit sap 1/1/5:1 create exit mesh-sdp 5001:5 create //sample LDP MPLS LSPs exit mesh-sdp 5005:5 create exit mesh-sdp 5006:5 create exit no shutdown exitEthernet-rings and sub-rings offer a way to build a scalable resilient Ethernet transport network. 0-7 multi ring hierarchy illustrates a hierarchical ring network using PBB where dual homed services are connected to a PBB based Ethernet ring network.
The major rings are connected by sub-rings to the top level major ring. These sub-rings require virtual channel and do not work with non-virtual channel. Ring flushing is contained to major rings, or in the case of a sub-ring link or node failure, to the sub-ring and the directly attached major rings.
