Chapter 13
| Basic Administration Protocols
Ethernet Ring Protection Switching
– 459 –
this ring node unblocks its ring ports. Otherwise, the block remains
unchanged. As a result, there is only one link with one end blocked.
The ring nodes stop transmitting R-APS (NR) messages when they accept
an R-APS (NR, RB – RPL Blocked), or when another higher priority request is
received.
■
Recovery with Revertive Mode – When all ring links and ring nodes
have recovered and no external requests are active, reversion is
handled in the following way:
a.
The reception of an R-APS (NR) message causes the RPL Owner
Node to start the WTR (Wait-to-Restore) timer.
b.
The WTR timer is cancelled if during the WTR period a higher
priority request than NR is accepted by the RPL Owner Node or is
declared locally at the RPL Owner Node.
c.
When the WTR timer expires, without the presence of any other
higher priority request, the RPL Owner Node initiates reversion by
blocking its traffic channel over the RPL, transmitting an R-APS (NR,
RB) message over both ring ports, informing the ring that the RPL is
blocked, and performing a flush FDB action.
d.
The acceptance of the R-APS (NR, RB) message causes all ring nodes
to unblock any blocked non-RPL link that does not have an SF
condition. If it is an R-APS (NR, RB) message without a DNF (do not
flush) indication, all ring nodes flush the FDB.
■
Recovery with Non-revertive Mode – In non-revertive operation, the
ring does not automatically revert when all ring links and ring nodes
have recovered and no external requests are active. Non-revertive
operation is handled in the following way:
a.
The RPL Owner Node does not generate a response on reception of
an R-APS (NR) messages.
b.
When other healthy ring nodes receive the NR (Node ID) message,
no action is taken in response to the message.
c.
When the operator issues the Clear command (Configure
Operation page) for non-revertive mode at the RPL Owner Node,
the non-revertive operation is cleared, the RPL Owner Node blocks
its RPL port, and transmits an R-APS (NR, RB) message in both
directions, repeatedly.
d.
Upon receiving an R-APS (NR, RB) message, any blocking node
should unblock its non-failed ring port. If it is an R-APS (NR, RB)
message without a DNF indication, all ring nodes flush the FDB.
■
Recovery for Forced Switching – A Forced Switch command is removed
by issuing the Clear command (Configure Operation page) to the same
ring node where Forced Switch mode is in effect. The clear command
Содержание GTL-2881
Страница 30: ...Figures 30 Figure 450 Showing RIP Peer Information 669 Figure 451 Resetting RIP Statistics 670 ...
Страница 34: ...Section I Getting Started 34 ...
Страница 48: ...Section II Web Configuration 48 Unicast Routing on page 651 ...
Страница 151: ...Chapter 4 Interface Configuration VLAN Trunking 151 Figure 69 Configuring VLAN Trunking ...
Страница 152: ...Chapter 4 Interface Configuration VLAN Trunking 152 ...
Страница 229: ...Chapter 8 Congestion Control Automatic Traffic Control 229 Figure 135 Configuring ATC Interface Attributes ...
Страница 230: ...Chapter 8 Congestion Control Automatic Traffic Control 230 ...
Страница 596: ...Chapter 14 Multicast Filtering Multicast VLAN Registration for IPv6 596 ...
Страница 620: ...Chapter 15 IP Configuration Setting the Switch s IP Address IP Version 6 620 ...
Страница 670: ...Chapter 18 Unicast Routing Configuring the Routing Information Protocol 670 Figure 451 Resetting RIP Statistics ...
Страница 672: ...Section III Appendices 672 ...
Страница 678: ...Appendix A Software Specifications Management Information Bases 678 ...
Страница 688: ...Appendix C License Statement GPL Code Statement Notification of Compliance 688 ...
Страница 696: ...Glossary 696 ...
Страница 706: ...GTL 2881 GTL 2882 E112016 ST R01 ...