R3303-HP HSR6800 Routers High Availability Configuration Guide

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requests are sent manually, whereas SF, SD, and WTR requests are sent automatically. If multiple
protection requests appear at the same time, the higher priority protection request is processed
preferentially. For example:
• The MS request sent by a station will not be processed if a higher priority protection request is
present on the RPR ring.
• If an FS request is present on the current ring, the SF or SD request automatically sent as the result
of a link failure will be processed only after the FS request is cleared.
Centralized RPR and distributed RPR
An RPR station is identical to an RPR logical interface bound with two RPR physical ports. The two RPR
physical ports are used to transmit data to or receive data from the ring. The RPR logical interface is
provided for you to make configuration.
Definitions
• If the two RPR physical ports are located on the same subcard, RPR is centralized.
• If the two RPR physical ports are located on different subcards, RPR is distributed.
Differences
The differences between distributed RPR and centralized RPR are:
• In centralized RPR, when the subcard where the two RPR physical ports are located goes down, the
RPR station fails.
• In distributed RPR, the down event of one subcard can cause the RPR physical port on the card to go
down and edge to the RPR station. The RPR station can still operate in protection mode to restore
services in 50 ms.
• In distributed RPR, if two RPR physical ports are on the same RPR station, you must connect their
mate ports with an optical fiber first for the RPR station to forward traffic.
RPR interface
RPR logical interface and RPR physical port overview
As described earlier, an RPR station comprises a pair of RPR physical ports, one is called the "east port"
and the other is called the "west port." Initially, the two ports were fixed on the device. The RPR station
could become unusable for the impairment of either port. To address the issue, the RPR logical interface
was introduced.
An RPR logical interface is identical to an RPR station. It can be bound with any two RPR physical ports.
When either of the RPR physical ports fails, you can replace it with another one. Moreover, as the
configuration on the RPR logical interface can be synchronized to the RPR physical ports, the
configuration procedure is streamlined.
Available RPR logical interface type is RPR interface (Layer 3 RPR logical interface) and available RPR
physical port type is RPRPOS. Each RPR physical port is accompanied by a mate port.
For a distributed RPR station to work, complete the following steps:
1. Create an RPR logical interface.
2. Bind the RPR physical ports with the RPR logical interface:
{ For an RPR station to work, you must bind its RPR logical interface with at least one RPR physical
port. With only one RPR physical port, the station is working in protection mode.