Enabling Lbd On Service-Access Interface; Lbd Packet Processing Mechanism For Lbd Service Access Ports - Alcatel-Lucent OmniSwitch 9900 Series Network Configuration Manual

Configuring Loopback Detection

Enabling LBD on Service-access Interface

By default, LBD is disabled for the switch and on all service-access ports. To globally enable LBD for the
switch, use the loopback-detection
-> loopback-detection enable
To enable LBD on a service-access port, use the
example:
-> loopback-detection service-access port 1/1/1 enable
LBD can also be enabled on link aggregates that are configured as service-access aggregates. For example,
the following command enables LBD on link aggregate 1:
-> loopback-detection service-access linkagg 1 enable
Consider the following when configuring LBD on a link aggregate:
•
The link aggregate must be formed by ports with same path cost.
•
LBD cannot be configured on linkagg which has member ports running LBD configuration and vice
versa.
•
When a linkagg is in violation or shutdown state, the member ports cannot be deleted from the linkagg.
Note. Before configuring the LBD using the "service-access" option, the port or link aggregate must be
configured for service access. Use the service access command, to configure the port or link aggregate for
service access. When LBD is enabled on ports without the 'service-access' keyword, the LBD behaves as
normal LBD feature.

LBD Packet Processing Mechanism for LBD Service Access Ports

The LBD packets on the service access ports are processed as follows:
1
If Virtual Private (VP) or Virtual Forwarding Instance (VFI) information is present in the packet
driver, then the LBD packet is processed else the packet is dropped.
2
The initiator session identifier (ISID) of the packet is extracted from the VP or VFI information and
compared with the LBD packet TLV ISID. If the ISID does not match, the packet is dropped.
3
If ISID matches, then the LBD packet TLV path cost is compared with the receiving LBD service
access port path cost. If the LBD path cost is lesser, the receiving access port is shut down. If LBD path
cost is higher, then the packet is dropped.
4
If path costs are equal, then LBD packet bridge MAC and receiving access port bridge MAC is
compared. If LBD packet bridge MAC is lesser, then the receiving access port is shutdown. If LBD Bridge
MAC is higher, then the packet is dropped.
5
If LBD packet bridge MAC and receiving access port bridge MAC are same (that is, same switch),
then LBD packet port ID and access port ID is compared. If LBD packet port ID is lesser, then the
receiving access port is shutdown. If LBD packet port ID is higher, then the packet is dropped.
OmniSwitch AOS Release 8 Network Configuration Guide
command. For example:
loopback-detection service-access
December 2017
LBD for Service Access Interface
command. For
page 7-9