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:
  

17 comments:

  1. hasifvpApril 4, 2013 at 9:59 PM

    Thanks!
    But can anybody share the ios used?

    ReplyDelete
  2. AnonymousJune 8, 2013 at 9:02 PM


    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
  3. UnknownFebruary 13, 2014 at 3:43 PM

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

    ReplyDelete
  4. AnonymousMarch 20, 2014 at 7:10 PM

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

    ReplyDelete
    Replies
    1. AnonymousMarch 20, 2014 at 7:38 PM

      MPLS is normally used for fast packet distribution.....

      Delete
  5. AnonymousMarch 21, 2014 at 12:58 AM

    any ways to compare between with and without MPLS implementation?

    ReplyDelete
  6. AnonymousMarch 22, 2014 at 4:21 PM

    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. AnonymousMarch 22, 2014 at 9:26 PM

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

      Delete
  7. UnknownMarch 20, 2016 at 1:07 PM

    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. UnknownMarch 23, 2016 at 3:13 PM

    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. AnonymousApril 20, 2016 at 8:44 AM

    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. AnonymousJune 25, 2016 at 9:26 PM

    Which ios version is used ??

    ReplyDelete
    Replies
    1. AnonymousNovember 8, 2017 at 8:50 PM

      I've used the image c3725-adventerprisek9-mz.124-15.T14 and it works fine for me.

      Delete
  11. Jhon TocasAugust 31, 2016 at 5:50 AM

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

    ReplyDelete
  12. AnonymousSeptember 17, 2016 at 2:34 AM

    Is this overlay config or L3 MPLS

    ReplyDelete
  13. AnonymousJanuary 8, 2018 at 1:37 PM

    why there is "TIB not enable" msg while checking mpls label ldp binding for a particular prifix.

    ReplyDelete

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