mpls

hello every body i have some questions if any one can answer me please ,
does MPLS consider a wan technology like frame-relay or ppp or it is only to make router looking at routing table faster because when i make configuration of MPLS on interface and i make # sh int S0/0 i found this interface run HDLC so mpls require layer 2 technology first is this right or what ?
and does mpls work on switches or router only ?
and another thing if the router look only to the label not the IP packet what will happen to the field in the packet like TTL and the CRC in the L3 header does the router will change them or will not see them only see the label number and forward

another one in stp
does port-fast send any bpdu towards PCs or it receive only ?

Comments

  • MartinLosikMartinLosik ✭✭✭
    edited March 23

    @Ashraf_12345 said:
    hello every body i have some questions if any one can answer me please ,

    another one in stp
    does port-fast send any bpdu towards PCs or it receive only ?

    Yes, port will send bpdu out but should not received any back.
    If u want to stop bpdus. U will need issue filter command.

  • MartinLosikMartinLosik ✭✭✭
    edited March 23

    I would not call MPLS WAN. it's often known as layer 2.5. aka something between layer 2 and 3. MPLS runs s inside of your ISP and is able to connect different wan technologies. Let's say u have frame relay wan and I have ATM. We are connected to same ISP who runs traffic over MPLS network.

    MPLS LDP protocol uses labels to route traffic over the Ethernet. You can only enable mpls on Ethernet interfaces. labels are assigned to networks in Rib. MPLS label has its own TTL field. internal mpls routers read and replace labels; edge routers read layer 3 info and will forward traffic using routeing table.

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