Virtual Leased Line Services
7750 SR OS Services Guide Page 211
VLL FR SAP Procedures
The operator enables the following CE address dynamic learning procedures by enabling the ce-
address-discovery option under the VLL service.
• Allow the service to come up without the CE address parameter configured at both the
SAP and spoke SDP. If one or both parameters are configured, they are ignored.
• The operator cannot configure the ce-address parameter under SAP or spoke SDP when
the ce-address-discovery option under the VLL service is enabled. Conversely, the
operator is not allowed to enable the ce-address-discovery option under the Ipipe service
if it has a SAP and/or spoke SDP with a user-entered ce-address parameter.
• If the 7750 SR receives an invFR ARP request message over the FR SAP, it updates the
ARP cache with the FR CE address. It also replies with the IP address of the CE attached
to the remote PE if a valid address was advertised in the address list TLV by this remote
PE. Otherwise, the router updates the ARP cache but does not reply to the invFR ARP.
• If the Ipipe service makes use of a spoke SDP, the 7750 SR includes the address list TLV
in the interface parameters field of the pseudowire FEC TLV in the label mapping
message. The address list TLV contains the current value of the CE address in the ARP
cache. If no address was learned, then an address value of 0.0.0.0 is used.
• If the remote PE included the address list TLV in the received label mapping message, the
local 7750 SR updates the remote PE node with the most current IP address of the FR CE
using a T-LDP status notification message containing an LDP address list. The
notification message is sent each time an IP address different from the current value in the
ARP cache is learned. This includes when the ARP is flushed and the CE address is reset
to the value of 0.0.0.00.
• If the remote PE did not include the address list TLV in the received label mapping
message, the local 7750 SR does not send any notification messages containing the
address list TLV during the lifetime of the IP pseudowire.
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