Alcatel-Lucent 7750 SR - Vll Cac; MC-Ring and VLL

Virtual Leased Line Services
7750 SR OS Services Guide Page 199
VLL CAC
This feature provides a method to administratively account for the bandwidth used by VLL
services inside an SDP which consists of RSVP LSPs.
The service manager keeps track of the available bandwidth for each SDP. The SDP available
bandwidth is applied through a configured booking factor. An administrative bandwidth value is
assigned to the spoke SDP. When a VLL service is bound to an SDP, the amount of bandwidth is
subtracted from the adjusted available SDP bandwidth. When the VLL service binding is deleted
from the SDP, the amount of bandwidth is added back into the adjusted SDP available bandwidth.
If the total adjusted SDP available bandwidth is overbooked when adding a VLL service, a
warning is issued and the binding is rejected.
This feature does not guarantee bandwidth to a VLL service as there is no change to the datapath
to enforce the bandwidth of an SDP by means such as shaping or policing of constituent RSVP
LSPs.
MC-Ring and VLL
To support redundant VLL access in ring configurations, the multi-chassis ring feature is
applicable to VLL SAPs. A conceptual drawing of the operation is shown in Figure 39. The given
CPE which is connected behind the ring node has access to both BSA through the same VLAN
provisioned in all ring nodes. There are two SAPs (with the same VLAN) provisioned on both
nodes.
If a closed ring status occurs, one of the BSAs becomes the master and it will signal an active
status bit on the corresponding VLL pseudowire. Similarly, the standby BSA will signal a standby
status. With this information, the remote node can choose the correct path to reach the CPE. In
case of a broken ring, the node that can reach the ring node that the given CPE is connected to by
RNCV check, will become master and will signal corresponding status on its pseudowire.
The mapping of individual SAPs to the ring nodes is done statically through CLI provisioning. In
order to keep the convergence time to a minimum, MAC learning must be disabled on the ring
node so all CPE originated traffic is sent in both directions. If the status is oper-down on the SAP
on the standby BSA, that part of the traffic will be blocked and not forwarded to the remote site.