Use this procedure to configure Ethernet ring protection (ERP).

The procedures in this section cover the following:

• Configuring a new Ethernet ring protection (ERP) ring.

• Adding a node to an Ethernet ring protection (ERP) ring.

• Deleting a node from an Ethernet ring protection (ERP) ring.

• Moving an RPL/RPL Owner node.

• Transitioning LNW170 in UNPROT mode to PROT.

• Transitioning LNW170 in PROT mode to UNPROT.

Ethernet ring protection provides switching for LNW70/170 Ethernet links connected in a ring configuration.

Figure 11-50, Ethernet ring protection shows a four-node ring. One of the links on Node 4 has been provisioned to be the Ring Protection Link (RPL). This is the link that by default is blocked for normal traffic. Node 4 is therefore the RPL Owner and blocks traffic bidirectionally. Switching is revertive – when a failure clears in the ring, the RPL is blocked (after a wait-to-restore delay). The ring has a VLAN dedicated to APS signaling, called the R-APS channel.

The LNW70 circuit pack supports switched and private line applications. The LNW170 offers all the features on the LNW70. In addition, the LNW170 can be equipped in pairs in an equipment protection configuration. There are 4 FE and 4 GbE LAN ports available on the LNW70/170. Up to 32 VCGs can be supported on the circuit pack. ERP is supported in protected and unprotected mode but only for switched applications.

Links supporting ERP are not required to all be the same rate; the ring can contain a mix of FE and GbE ports, or it can contain a mix of VCGs with different bandwidths, or a mix of FE/GbE ports and VCGs. It is up to the user/network designer to make sure that the ERP ring is appropriately sized for the application.

The following are some considerations for ERP support on LNW70/170:

• ERP is supported on optical and electrical SFP-based LAN ports on the LNW70/170, as well as the VCGs.

  Note that protection switch times are 50 msec. Detection times have been optimized for optical ports only.

• LNW70/170 vlantagmd must be set to SWITCHED.

• LCAS protection should be disabled on VCGs that are ERP-controlled by keeping the LCAS Hold-off Timer set to 99999 (Infinity).

• When the companion slots are equipped with LNW170, the ports on two circuit packs may be working independently when the circuit pack slot protection state is provisioned as UNPROT, or paired LAN ports 1, 2, 5 and 6 may be in a equipment protection mode when provisioned as PROT. Ports 3, 4, 7 and 8 cannot be used.

• In equipment-unprotected mode (Slot Protection State = UNPROT), the following is supported:

  • LAN-based ERP across any 2 ports.

    See Figure 11-51, ERP on LNW70/170 unprotected LAN ports.

  • VCG-based ERP across any 2 VCGs.

    See Figure 11-52, ERP on LNW70/170 unprotected VCG ports.

  • A combined LAN-and-VCG-based ERP.

• In equipment-protected mode (Slot Protection State = PROT), the following is supported:

  • VCG-based ERP across any 2 pair of equipment-protected VCGs is supported.

    See Figure 11-53, ERP on LNW170 protected VCG ports.

• UNPROT to PROT transitions are not allowed if there are any LAN-based ERPs, but are allowed with VCG-based ERPs

• Four LAN ERP instances per UNPROT circuit pack is supported. In addition to the LAN port, ERP on VCG ports is also supported. For a protected LNW170 in DMX/DMXtend, up to 16 ERP instances is supported on VCGs.

  For an unprotected LNW70/170 in DMX/DMXtend up to 20 ERP instances (main or sub-ring) is supported (on VCGs and/or Ethernet ports).

ERP

Figure 11-50: Ethernet ring protection

ERP on LAN ports (UNPROT)

Figure 11-51: ERP on LNW70/170 unprotected LAN ports

ERP on VCG ports (UNPROT)

Figure 11-52: ERP on LNW70/170 unprotected VCG ports

ERP on LNW170 VCG ports (PROT)

Figure 11-53: ERP on LNW170 protected VCG ports

Dual Ring Interconnection - G.8032v1 Amendment 1

In dual ring interconnection (DRI), two ERP rings “share” a segment. In its simplest form a segment is composed of two interconnection nodes (ICN) and a shared link. For example, see Figure 11-54, Basic DRI with ERP. Only one of the rings takes responsibility for protecting the shared link. This is the “Main” ring. The other ring is called “Sub” ring. The Main ring is responsible for tunneling the R-APS PDUs of the sub-ring. This is called the R-APS virtual channel.

The Main ring and its sub-ring use different R-APS VLANs. The R-APS VLAN of the sub ring is considered regular data traffic for the Main ring (and is protected as such). Only ICN nodes need to be DRI-aware. A node is an ICN node if it has a sub-ring terminating on a main ring. Other (non-ICN) nodes simply run the single-ring ERP (and in fact don’t know if they belong to a main ring or sub ring).

The two rings work independently, the main ring controlling the shared segment. They each have an RPL. A protection switch in the Main ring does not affect the sub-ring because the sub ring should still be able to hand off traffic to the Main ring via either of the interconnection nodes. This is also true if the shared link fails.

Figure 11-54: Basic DRI with ERP

Rings can be cascaded into a ladder configuration. A sub-ring assumes the role of main ring for another sub-ring. See Figure 11-55, ERP DRI ladder example.

Rings may be multi-ring. Two (or more) sub-rings are connected to the same Main ring over the same shared link. See Figure 11-56, ERP DRI multi-ring example.

Figure 11-55: ERP DRI ladder example

Figure 11-56: ERP DRI multi-ring example

ERP parameters

Table 11-16: ERP configuration parameters (ent-erp)

CIT Parameter	Description	TL1 ent-erp command parameter
ERP ID	An alphanumeric string of up to 32 characters. It may not contain a hyphen (“-”). The ERP ID must be unique per slot. The ERP ID has no network-wide significance.There is no requirement that the same ERP ID must be provisioned on the port(s) at the remote network element(s) to which the port(s) at this network element are connected.	erpid
Virtual Switch ID	Virtual Switch ID. Value: An integer in the range 1 to 16.	vrtswid
Port 1	Port #1 of the ERP port list. This is a required parameter. The erpport value is an ampersand-separated list of 2 port AIDs, Port 1 and Port 2. Ports: Port 1 can be an Ethernet or VCG port. Port cannot be an Ethernet port if the circuit pack is in Protected mode. Port 1 and Port 2 must have the same Port Role (either CUSTOMER or NETWORK). The port cannot have the CUSTOMER port role and belong to a virtual switch with Virtual LAN Tagging Mode (tagmd) of Transparent. Port 1 and Port 2 must be in the same virtual switch specified above. The port cannot be part of a spanning tree, or LAG, or another ERP instance.	ERPport
Port 2	Port 2 of the ERP port list. This is a required parameter. See the requirement for Port 1 above. Port 2 can also be an ERP ID or Ethernet or VCG port. In case of a sub-ring ERP, this refers to the Main ERP that this sub-ring is connected to.	ERPport
VLAN ID	VLAN ID used for ERP signaling. The VLAN ID cannot be used in the VLAN or Port Tag for the VLAN management. This is a required parameter. Valid values are: an integer in the range 1-4093. The vlan must be unique among all sub-rings attached to the same main ring.	vlan
RPL ID	Ring Protection Link ID. It is either Port 1 or Port 2. A ring requires one (and only one) RPL. This parameter is optional. Note that the user can add or delete the RPL from the ERP. The TL1 command/parameters to use is ED-ERP:addprotlink/delprotlink.
Wait to Restore	Wait-to-Restore timer. Valid values: an integer in the range of 1-12 minutes. The default value is 5 min. The parameter applies if the RPL ID (see above) is provisioned.	wtr
Guard Timer	Guard timer. Valid values: an integer in the range 10-2000 milliseconds in steps of 10 msec. Default is 500 msec. Prevents nodes from reacting to outdated information.	guard
MD Level	Maintenance Domain level. Valid values: an integer in the range 0-7. The default value is 1. It is the service OAM maintenance domain level used in the ERP signaling control messages (R-APS).	mdlevel
Propagation TC Message	Controls enabling propagation of Topology Change (TC) messages. Valid values : Enable or Disable. The default value is Disable. Only applies to sub-ring ERP instances where the sub-ring interconnects with its Main ring and controls whether a sub-ring topology change results in a TC message in the main ring.	proptc
ERP State	Controls enabling the ERP instance. Valid values : Enable or Disable. The default value is Enable. When an ERP instance is disabled, it no longer participates in ERP signaling. Port block/unblock states remain unchanged and ERP messages are still forwarded (unless one of the ports is blocked).	state
R-APS PDU Priority	R-APS PDU priority. Represents the encoding of the p-bits in the R-APS VLAN tag. Valid values: an integer in the range of 0-7. The default value is 7. In order for the p-bits to traverse the ERP ports, the ERP port must have a porttype of BOUNDARY.	pri