huawei router in setting up LSP introduces below, have to notice that some of the problems, to establish how to cancel the session after the LSP and loop testing, using a wireless router, often set up LSP leakage problems, and the initial password and access to the Internet often dropped.
a, the LDP, by detecting the session connection transmission LDPPDU to determine the integrity of the session, LSR build a living condition for each session timer, each received a LDPPDU refresh the timer, if before receiving new LDPPDU timer timeout, interruption of LSR think session, peer relationship failure.LSR will close the corresponding transport layer connection, terminate the session.
second and set up LSP in MPLS domain will prevent the loop, the LDP can create the appearance of LSP loop loop detection mechanism, and to avoid the label request message occurs in the loop.
1, in the passed label binding information contained in the message the hop, each after a jump the value plus one, when the maximum value in excess of the prescribed that a loop, termination of LSP process is established.
2, record information in the label binding messages, each after a jump, the corresponding LSR can check whether your ID in the records.If not, your ID is added to the record, if any, that the loop, termination of LSP process is established.
three, MPLS also support the LDP mechanism based on constraint route, the so-called CR - the LDP, is the entrance to the node when initiated by LSP, to establish LSP in label request message routing is attached to certain constraints, these constraints can be precisely specified on the LSR namely one specified based on LSP LSR, right now is called strict explicit routing, we can also be a corresponding to choose downstream LSR fuzzy restrictions, which only specify based on LSP individual LSR, called loose explicit routing at this time.
jump by four, the LDP by establishing LSP, our attention is here to take advantage of each LSR routing along the turn of the published information to determine the next jump, and routing to the information in the published is usually collected through IGP, BGP routing protocols.But the LDP is not direct and related to all kinds of routing protocol, only the indirect use of routing information.
five, the LDP is specially used to implement the label distribution protocol, but the LDP is not the only label distribution protocol, such as BGP, RSVPS extend existing protocols, can also support the MPLS label distribution, MPLS application also needs to extend some routing protocols.
the RSVPS, resource reserve agreement after extension can support MPLS label distribution, at the same time, binding messages tag for transmission, can also carry resources reserved information, LSP can be developed by this method has the function of resources reserve, the expansion of the RSVP protocol primarily in its Path and adding new objects Resv message news, these new objects besides can carry labels binding information, also can bring the limitation on the LSR zin along the diameter when information, so as to support the LSP constrained routing functions.