MPLS Network Configuration on GNS3:


What is MPLS (Multi-Protocol Label Switching) ?
MPLS is lable base fast switching, MPLS is a technique which forward the packets in network on bases of labels.

Why MPLS?
Router use the process switching in which whenever router received a packet it checks its IP address match with routing table and forward packet, send ARP request for MAC addres. This Process become a little slow when router dealing with a lot of IP packets, in case of VOIP e.g. a IP-Phone call may using 50packets/second then router have to perform process switching for every packets  


But in MPLS instead of processing above large packet each time route just use a label to forward a packet which saving some processing cycle and made fast forwarding.

MPLS Configuration on GNS3:


Design above lab in gns3 and configure IP address and EIGRP according to EIGRP configuration on GNS3 . In our lab R3 is provider router where as R2, R4 and R5 are the provider edge routers.
On Cisco router to enable the MPLS you required to :
  1. Enable CEF(cisco express forwarding) on router
  2. Change MTU (maximum transmission unit) from 1500 to 1512 on MPLS enabled interfaces, becase MPLS header is of 4 bytes and one interface have maximum of three.
R2 MPLS configuration Commmands:
R2#conf t
R2(config)#ip cef
R2(config)#int s1/1
R2(config-if)#mpls label protocol ldp
R2(config-if)# mpls ip
R2(config-if)# mpls mtu 1512
R2(config-if)#ip route-cache cef

R3 MPLS configuration Commmands:
R3(config)#ip cef
R3(config)#int s1/1
R3(config-if)#ip route-cache cef
R3(config-if)#mpls mtu 1512
R3(config-if)#mpls ip
R3(config-if)#mpls label protocol ldp
R3(config-if)#int s1/2
R3(config-if)#mpls mtu 1512
R3(config-if)#ip route-cache cef
R3(config-if)#mpls ip
R3(config-if)#mpls label protocol ldp
R3(config)#int s1/0
R3(config-if)#mpls mtu 1512
R3(config-if)#ip route-cache cef
R3(config-if)#mpls ip
R3(config-if)#mpls label protocol ldp

R4 MPLS configuration Commmands:
R4(config)#ip cef
R4(config)#int s1/0
R4(config-if)# mpls ip
R4(config-if)#mpls label protocol ldp
R4(config-if)# mpls mtu 1512

R5 MPLS configuration Commmands:
R5(config)#ip cef
R5(config)#int s1/0
R5(config-if)# mpls label protocol ldp
R5(config-if)# mpls ip
R5(config-if)# mpls mtu 1512
R5(config-if)#
R5(config-if)#ip route-cache cef

MPLS Verification Commands:

R3#show mpls ldp neighbor


R3#show mpls forwarding-table


R3#show ip cef



R3#sh mpls ip binding




R3#sh mpls forwarding-table interface serial 1/1

Learn About OSPF, IS IS and EIGRP.
Download MPLS Books:
  

16 comments:

  1. Thanks!
    But can anybody share the ios used?

    ReplyDelete

  2. Please, can you help me???

    R2(config)#
    R2(config)#
    R2(config)#ip cef
    R2(config)#
    R2(config)#
    R2(config)#
    R2(config)#interface serial 1/1
    R2(config-if)#
    R2(config-if)#
    R2(config-if)#mpls
    R2(config-if)#mpls
    R2(config-if)#mpls
    R2(config-if)#mpls
    R2(config-if)#mpls label
    R2(config-if)#mpls label prot
    R2(config-if)#mpls label protocol ldp
    ^
    % Invalid input detected at '^' marker.

    R2(config-if)#

    ReplyDelete
    Replies
    1. This may be Router Can't Support MPLS .

      :)

      Delete
  3. can u send MP-BGP configuration exmple in gns3??
    Mail : xxx2092@gmail.com

    ReplyDelete
  4. Hi, Can I ack a question. What is the differences before and after implementing the MPLS into the network ?

    ReplyDelete
    Replies
    1. MPLS is normally used for fast packet distribution.....

      Delete
  5. any ways to compare between with and without MPLS implementation?

    ReplyDelete
  6. What is the used of this 2 commands ?? Thanks and appreciated for your answer.
    R3(config-if)#ip route-cache cef
    R3(config-if)#mpls ip

    ReplyDelete
    Replies
    1. This command ensures Cisco Express Forwarding (CEF) switching is done for packets that enter this interface.

      Delete
  7. By implementing the above page as it is, can I configure and implement Mpls topology? Also, what are the pre-requisites required in my computer to implement it? Please help.

    ReplyDelete
  8. hey man!thanks for it but would u upload the the whole conf for the whole router?
    and the config for the coustomer site?

    ReplyDelete
  9. R1(config)#ip cef
    R1(config)#int s1/1
    R1(config-if)#mpls label protocol ldp
    ^
    % Invalid input detected at '^' marker.

    I have the above result when trying to simulate mpls network. What router should I use on hp corei3 4GB ram 64 bit OS

    ReplyDelete
  10. Which ios version is used ??

    ReplyDelete
  11. If only use:
    Int serial x/y
    Mpls ip
    !
    Cisco routers up ldp.neighbors

    ReplyDelete
  12. Is this overlay config or L3 MPLS

    ReplyDelete

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