Lab 2 - MPLS LDP

MPLS LDP enables LSRs to discover other LDP peers and establish sessions with those potential peers for the purpose of exchanging label binding information. MPLS uses LDP and the exchanged label binding information to create label switching paths. In this lab we will look at the following LDP related concepts.

Concepts tested

• LDP router ID
• OSPF LDP Autoconfig
• Direct and indirect LDP peering
• Targeted LDP peering
• LDP discovery peering
• LDP peering authentication

Lab Tasks:

• Enable MPLS LDP peering using UDP multicast between R1-R2 using their directly connected interfaces for the LDP tcp peering connection.
• Use only a single command on R1 to enable LDP on all OSPF enabled interfaces
• Enable MPLS LDP between R2-R3 using UDP unicast ensure that router R2 is the active LSR router for that peering session and that their loopback addresses are used to establish the LDP tcp peering connection.
• Enable MPLS LDP between R1-R3 using LDP IGP synchronization using the routers directly connnected links for TCP session establishment.
• Ensure each router's LDP router ID is the local LSRs loopback 0 address.
• Enable authentication on all LDP sessions using MD5 with the password CCIE
• OSPF has been configured already for you.

GNS3 configuration file, requires IOS v15 for the 7200 router: Link

Solution Below:

R1 Configuration

R1(config)#mpls ip
R1(config)#mpls ldp router-id loopback 0 force

R1(config)#mpls ldp password required

R1(config)#mpls ldp neighbor 2.2.2.2 password CCIE
R1(config)#mpls ldp neighbor 3.3.3.3 password CCIE
R1(config)#int gig0/0
R1(config-if)#mpls ldp discovery transport-address interface
R1(config-if)#exit
R1(config)#int gig1/0
R1(config-if)#mpls ldp discovery transport-address interface
R1(config-if)#exit
R1(config)#router ospf 1
R1(config-router)#mpls ldp autoconfig
R1(config-router)#end
R1#

R2 Configuration

R2(config)#mpls ip
R2(config)#mpls ldp router-id loopback 0 force
R2(config)#mpls ldp password required
R2(config)#mpls ldp neighbor 1.1.1.1 password CCIE
R2(config)#mpls ldp neighbor 3.3.3.3 password CCIE
R2(config)#mpls ldp neighbor 3.3.3.3 targeted ldp
R2(config)#int g0/0
R2(config-if)#mpls ldp discovery transport-address interface
R2(config-if)#mpls ip
R2(config-if)#exit
R2(config)#end
R2#

R3 Configuration

R3(config)#mpls ip
R3(config)#mpls ldp router-id loopback 0 force
R3(config)#mpls ldp password required
R3(config)#mpls ldp neighbor 1.1.1.1 password CCIE
R3(config)#mpls ldp neighbor 2.2.2.2 password CCIE
R3(config)#mpls ldp password required
R3(config)#mpls ldp neighbor 1.1.1.1 password CCIE
R3(config)#mpls ldp discovery targeted-hello accept
R3(config)#int g0/0
R3(config-if)#mpls ldp discovery transport-address interface
R3(config-if)#mpls ip
R3(config-if)#exit
R3(config)#end
R3#

R1 Verification


R1#debug mpls ldp transport events
LDP transport events debugging is on
*Oct 18 12:17:03.091: ldp: Send ldp hello; GigabitEthernet0/0, src/dst 120.0.12.1/224.0.0.2, inst_id 0
*Oct 18 12:17:03.207: ldp: Send ldp hello; GigabitEthernet1/0, src/dst 120.0.13.1/224.0.0.2, inst_id 0

Above verifies that R1 is sending hellos to the all routers multicast address 224.0.0.2 as required by the lab tasks.

%LDP-5-NBRCHG: LDP Neighbor 2.2.2.2:0 (1) is UP

After the multicast hellos are sent and received LDP peering is established with both R2 and R3.

Below shows that the TCP connection was established using the directly connected interfaces and MD5 authentication was used.

R1#sh mpls ldp neighbor detail
    Peer LDP Ident: 2.2.2.2:0; Local LDP Ident 1.1.1.1:0
        TCP connection: 120.0.12.2.39350 - 120.0.12.1.646; MD5 on
        Password: required, neighbor, in use
        State: Oper; Msgs sent/rcvd: 28/28; Downstream; Last TIB rev sent 12
        Up time: 00:16:54; UID: 1; Peer Id 0
        LDP discovery sources:
          GigabitEthernet0/0; Src IP addr: 120.0.12.2
            holdtime: 15000 ms, hello interval: 5000 ms
        Addresses bound to peer LDP Ident:
          120.0.12.2      120.0.23.2      2.2.2.2
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Capabilities Sent:
<snip>
    Peer LDP Ident: 3.3.3.3:0; Local LDP Ident 1.1.1.1:0
        TCP connection: 120.0.13.3.34335 - 120.0.13.1.646; MD5 on
        Password: required, neighbor, in use
        State: Oper; Msgs sent/rcvd: 13/13; Downstream; Last TIB rev sent 12
        Up time: 00:04:08; UID: 2; Peer Id 1
        LDP discovery sources:
          GigabitEthernet1/0; Src IP addr: 120.0.13.3
            holdtime: 15000 ms, hello interval: 5000 ms
        Addresses bound to peer LDP Ident:
          120.0.23.3      120.0.13.3      3.3.3.3
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Capabilities Sent:
<snip>

R2 Verification

R2#debug mpls ldp transport events
LDP transport events debugging is on
ldp: Send ldp dir hello; no interface, src/dst 2.2.2.2/3.3.3.3, inst_id 0

ldp: Send ldp hello; GigabitEthernet0/0, src/dst 120.0.12.2/224.0.0.2, inst_id 0

Above shows R2 sending a multicast LDP hello to R1 and a directed LDP hello to R3 as required.

%LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (1) is UP
%LDP-5-NBRCHG: LDP Neighbor 3.3.3.3:0 (2) is UP

Peering is established with both R1 and R3.

R2#sh mpls ldp neighbor detail
    Peer LDP Ident: 1.1.1.1:0; Local LDP Ident 2.2.2.2:0
        TCP connection: 120.0.12.1.646 - 120.0.12.2.39350; MD5 on
        Password: required, neighbor, in use
        State: Oper; Msgs sent/rcvd: 37/36; Downstream; Last TIB rev sent 12
        Up time: 00:24:07; UID: 1; Peer Id 0
        LDP discovery sources:
          GigabitEthernet0/0; Src IP addr: 120.0.12.1
            holdtime: 15000 ms, hello interval: 5000 ms
        Addresses bound to peer LDP Ident:
          120.0.12.1      120.0.13.1      1.1.1.1
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Capabilities Sent:
<snip>
    Peer LDP Ident: 3.3.3.3:0; Local LDP Ident 2.2.2.2:0
        TCP connection: 3.3.3.3.27549 - 2.2.2.2.646; MD5 on
        Password: required, neighbor, in use
        State: Oper; Msgs sent/rcvd: 30/31; Downstream; Last TIB rev sent 12
        Up time: 00:19:37; UID: 2; Peer Id 1
        LDP discovery sources:
          Targeted Hello 2.2.2.2 -> 3.3.3.3, active;
            holdtime: infinite, hello interval: 10000 ms
        Addresses bound to peer LDP Ident:
          120.0.23.3      120.0.13.3      3.3.3.3
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Clients: Dir Adj Client
        Capabilities Sent:
<snip>

Above verifies TCP connectivity per the lab requirements as well as MD5 authentication.

R3 Verification

R3#debug mpls ldp transport events
LDP transport events debugging is on

ldp: Rcvd ldp dir hello to 3.3.3.3 from 2.2.2.2 (2.2.2.2:0); GigabitEthernet0/0; opt 0xF

ldp: Send ldp hello; GigabitEthernet1/0, src/dst 120.0.13.3/224.0.0.2, inst_id 0

Above verifies that R3 is sending a multicast hello to R1 and receiving a directed hello from R2.

%LDP-5-NBRCHG: LDP Neighbor 2.2.2.2:0 (1) is UP
%LDP-5-NBRCHG: LDP Neighbor 1.1.1.1:0 (2) is UP

Above verifies LDP peering with R1 and R2.

R3#sh mpls ldp neighbor det
    Peer LDP Ident: 2.2.2.2:0; Local LDP Ident 3.3.3.3:0
        TCP connection: 2.2.2.2.646 - 3.3.3.3.27549; MD5 on
        Password: required, neighbor, in use
        State: Oper; Msgs sent/rcvd: 38/37; Downstream; Last TIB rev sent 12
        Up time: 00:25:40; UID: 1; Peer Id 0
        LDP discovery sources:
          Targeted Hello 3.3.3.3 -> 2.2.2.2, passive;
            holdtime: 90000 ms, hello interval: 10000 ms
        Addresses bound to peer LDP Ident:
          120.0.12.2      120.0.23.2      2.2.2.2
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Capabilities Sent:
<snip>
    Peer LDP Ident: 1.1.1.1:0; Local LDP Ident 3.3.3.3:0
        TCP connection: 120.0.13.1.646 - 120.0.13.3.34335; MD5 on
        Password: required, neighbor, in use
        State: Oper; Msgs sent/rcvd: 28/29; Downstream; Last TIB rev sent 12
        Up time: 00:17:23; UID: 2; Peer Id 1
        LDP discovery sources:
          GigabitEthernet1/0; Src IP addr: 120.0.13.1
            holdtime: 15000 ms, hello interval: 5000 ms
        Addresses bound to peer LDP Ident:
          120.0.12.1      120.0.13.1      1.1.1.1
        Peer holdtime: 180000 ms; KA interval: 60000 ms; Peer state: estab
        Capabilities Sent:
<snip>

Above verifies TCP connectivity per the lab requirements as well as MD5 authentication.


Sources:

http://www.cisco.com/c/en/us/td/docs/ios/12_4t/12_4t2/ftldp41.html#wp1651403

http://www.cisco.com/c/en/us/td/docs/ios/12_4t/12_4t2/ftldp41.html

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_ldp/configuration/12-4m/mp-ldp-12-4m-book.pdf