MPLS Label Assignment and Distribution Link to heading
1. Discovering LDP Neighbors Link to heading
Session Establishment
Step 1: LDP Discovery Link to heading
- 2 methods of neighbor discovery:
- Basic: discover directly connected LSR neighbors. An LSR sends out periodic Hellos as UDP (port 646) to multicast address 224.0.0.2.
- Extended: discover non-directly connected neighbors. An LSR sends out unicast Targeted Hellos as UDP to the IP address of the targeted LSR.
# mpls ldp neighbor 192.168.1.1 targeted ldp
Step 2: LDP Session Establishment Link to heading
- After the exchange of Hellos, LDP session is established:
- 2 LSRs elect ative and passive roles by comparing the source IP address.
- TCP (port 646) is used to establish the session.
- Negotiate parameters by using Initialization messages.
2. Frame-mode MPLS Link to heading
MPLS Label Space: Link to heading
- Per-Interface: Labels are assigned per FEC per interface => Packets are forwarded based on both the incoming label and interface.
- Per-platform: Labels assigned per FEC are the same on any interface => Packets are forwarded based on incoming label only.
MPLS Label distribution modes: Link to heading
- Downstream on-demand: each LSR sends a label binding request to its downstream router only (ex: RSVP for TE).
- Unsolicited Downstream: each LSR automatically distributes its label bindings to all peers without a request message.
MPLS Label retention modes: Link to heading
- Liberal: every label received from a neighbor is retained in LIB => Advantage: quick reaction to topology changes.
- Conservative: label will only be retained if the sending LSR is the next hop downstream router for the specific FEC => Advantage: more secure than liberal mode.
MPLS Label Control modes: Link to heading
- Independent label distribution: An LSR assigns a local binding to a FEC as soon as it realizes its existence in the routing table, does not wait to receive any labels from other LSR.
- Ordered label distribution: An LSR assigns a local binding to a FEC only if it recognizes it is the egress LSR for that FEC or if it receives a label binding from the next hop LSR.
Frame-mode MPLS parameters include: Link to heading
- Per-platform label address space
- Unsolicited downstream label distribution
- Independent control for label allocation
- Liberal label retention
MPLS L3 VPN Link to heading
Task 1 Link to heading
Configure in ISP:
- OSPF 1 Area 0 on all routers.
- BGP on R1 and R3, using Lo0 to form peering.
- MPLS on all routers.
Configuration Link to heading
hostname R1
int l0
ip add 1.1.1.1 255.255.255.255
int f0/0
no shut
ip add 192.168.12.1 255.255.255.0
int f0/1
no shut
ip add 192.168.14.1 255.255.255.0
int f1/0
no shut
ip add 192.168.16.1 255.255.255.0
int f1/1
no shut
ip add 192.168.18.1 255.255.255.0
router ospf 1
net 1.1.1.1 0.0.0.0 area 0
net 192.168.12.0 0.0.0.255 area 0
router bgp 123
neighbor 3.3.3.3 remote-as 123
neighbor 3.3.3.3 update-source l0
int f0/0
mpls ip
hostname R2
int f0/0
no shut
ip add 192.168.12.2 255.255.255.0
int f0/1
no shut
ip add 192.168.23.2 255.255.255.0
router ospf 1
net 192.168.12.0 0.0.0.255 area 0
net 192.168.23.0 0.0.0.255 area 0
int range f0/0-1
mpls ip
hostname R3
int l0
ip add 3.3.3.3 255.255.255.255
int f0/0
no shut
ip add 192.168.23.3 255.255.255.0
int f0/1
no shut
ip add 192.168.35.3 255.255.255.0
int f1/0
no shut
ip add 192.168.37.3 255.255.255.0
int f1/1
no shut
ip add 192.168.39.3 255.255.255.0
router ospf 1
net 3.3.3.3 0.0.0.0 area 0
net 192.168.23.0 0.0.0.255 area 0
router bgp 123
neighbor 1.1.1.1 remote-as 123
neighbor 1.1.1.1 update-source l0
int f0/0
mpls ip
Verification Link to heading
R1#show ip bgp
BGP router identifier 1.1.1.1, local AS number 123
BGP table version is 1, main routing table version 1
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
3.3.3.3 4 123 2 2 1 0 0 00:00:18 0
R1#show mpls int
Interface IP Tunnel BGP Static Operational
FastEthernet0/0 Yes (ldp) No No No Yes
Task 2 Link to heading
Configure in Customer A:
- Create VRF A on router R1 and R3 (RD = 1:1, RT = 10:10).
- Configure Static route on all routers.
- Redistribute Static to MP-BGP
Configuration Link to heading
The exchange of IPv4 routes between BGP neighbors is enabled by default.
=> no bgp default ipv4-unicast disables the default exchange.
=> Neighbors that need to receive IPv4 routes have to be activated for route exchange.
R1(config)#
ip vrf A
rd 1:1
route-target 10:10
int f0/1
ip vrf forward A
ip add 192.168.14.1 255.255.255.0
ip route vrf A 4.4.4.4 255.255.255.255 192.168.14.4
router bgp 123
no bgp default ipv4-unicast
address-family vpnv4
neighbor 3.3.3.3 activate
neighbor 3.3.3.3 send-community extended
address-family ipv4 vrf A
redistribute static
R3(config)#
ip vrf A
rd 1:1
route-target 10:10
int f0/1
ip vrf forward A
ip add 192.168.35.3 255.255.255.0
ip route vrf A 5.5.5.5 255.255.255.255 192.168.35.5
router bgp 123
no bgp default ipv4-unicast
address-family vpnv4
neighbor 1.1.1.1 activate
neighbor 1.1.1.1 send-community extended
address-family ipv4 vrf A
redistribute static
hostname R4
int l0
ip add 4.4.4.4 255.255.255.255
int f0/0
no shut
ip add 192.168.14.4 255.255.255.0
ip route 5.5.5.5 255.255.255.255 192.168.14.1
hostname R5
int l0
ip add 5.5.5.5 255.255.255.255
int f0/0
no shut
ip add 192.168.35.5 255.255.255.0
ip route 4.4.4.4 255.255.255.255 192.168.35.3
Verification Link to heading
R1#show ip bgp vpnv4 vrf A
BGP table version is 4, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
x best-external, a additional-path, c RIB-compressed,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf A)
*> 4.4.4.4/32 192.168.14.4 0 32768 ?
*>i 5.5.5.5/32 3.3.3.3 0 100 0 ?
R4#ping 5.5.5.5 source 4.4.4.4
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
Packet sent with a source address of 4.4.4.4
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 500/662/784 ms
Task 3 Link to heading
Configure in Customer B:
- Create VRF B on router R1 and R3 (RD = 2:2, RT = 20:20).
- Configure MPLS VPN to connect 2 sides R4 and R5.
- Configure EIGRP 100 on all routers.
- Redistribute EIGRP to MP-BGP.
- Redistribute only 1 route Lo0 from MP-BGP to EIGRP (using route-map).
Configuration Link to heading
R1(config)#
ip vrf B
rd 2:2
route-target 20:20
int f1/0
ip vrf forward B
ip add 192.168.16.1 255.255.255.0
router eigrp 100
address-family ipv4 vrf B autonomous-system 100
no auto
net 192.168.16.0 0.0.0.255
router bgp 123
address-family ipv4 vrf B
redistribute eigrp 100
ip access-list standard CUSTB
permit host 7.7.7.7
route-map CUSTB_REDISTRIBUTE permit 10
match ip add CUSTB
router eigrp 100
address-family ipv4 vrf B autonomous-system 100
default-metric 100000 10 255 1 1500
redistribute bgp 123 route-map CUSTB_REDISTRIBUTE
R3(config)#
ip vrf B
rd 2:2
route-target 20:20
int f1/0
ip vrf forward B
ip add 192.168.37.3 255.255.255.0
router eigrp 100
address-family ipv4 vrf B autonomous-system 100
no auto
net 192.168.37.0 0.0.0.255
router bgp 123
address-family ipv4 vrf B
redistribute eigrp 100
ip access-list standard CUSTB
permit host 6.6.6.6
route-map CUSTB_REDISTRIBUTE permit 10
match ip add CUSTB
router eigrp 100
address-family ipv4 vrf B autonomous-system 100
default-metric 100000 10 255 1 1500
redistribute bgp 123 route-map CUSTB_REDISTRIBUTE
hostname R6
int l0
ip add 6.6.6.6 255.255.255.255
int f0/0
no shut
ip add 192.168.16.6 255.255.255.0
router eigrp 100
no auto
net 6.6.6.6 0.0.0.0
net 192.168.16.0 0.0.0.255
hostname R7
int l0
ip add 7.7.7.7 255.255.255.255
int f0/0
no shut
ip add 192.168.37.7 255.255.255.0
router eigrp 100
no auto
net 7.7.7.7 0.0.0.0
net 192.168.37.0 0.0.0.255
Verification Link to heading
R1#show ip bgp vpnv4 vrf B
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 2:2 (default for vrf B)
*> 6.6.6.6/32 192.168.16.6 156160 32768 ?
*>i 7.7.7.7/32 3.3.3.3 156160 100 0 ?
*> 192.168.16.0 0.0.0.0 0 32768 ?
*>i 192.168.37.0 3.3.3.3 0 100 0 ?
R6#show ip route eigrp
7.0.0.0/32 is subnetted, 1 subnets
D 7.7.7.7 [90/158720] via 192.168.16.1, 00:00:31, FastEthernet0/0
R6#ping 7.7.7.7 source 6.6.6.6
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 7.7.7.7, timeout is 2 seconds:
Packet sent with a source address of 6.6.6.6
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 520/599/700 ms
Task 4 Link to heading
Configure in Customer C:
- Create VRF C on router R1 and R3 (RD = 3:3, RT = 30:30).
- Configure MPLS VPN to connect 2 sides R8 and R9.
- Configure OSPF 100 Area 0 on all routers.
- Redistribute OSPF to MP-BGP.
- Redistribute only 1 route Lo0 from MP-BGP to OSPF (using route-map).
Configuration Link to heading
R1(config)#
ip vrf C
rd 3:3
route-target 30:30
int f1/1
ip vrf forward C
ip add 192.168.18.1 255.255.255.0
router ospf 100 vrf C
net 192.168.18.0 0.0.0.255 area 0
router bgp 123
address-family ipv4 vrf C
redistribute ospf 100
ip access-list standard CUSTC
permit host 9.9.9.9
route-map CUSTC_REDISTRIBUTE permit 10
match ip add CUSTC
router ospf 100 vrf C
redistribute bgp 123 route-map CUSTC_REDISTRIBUTE subnets
R3(config)#
ip vrf C
rd 3:3
route-target 30:30
int f1/1
ip vrf forward C
ip add 192.168.39.3 255.255.255.0
router ospf 100 vrf C
net 192.168.39.0 0.0.0.255 area 0
router bgp 123
address-family ipv4 vrf C
redistribute ospf 100
ip access-list standard CUSTC
permit host 8.8.8.8
route-map CUSTC_REDISTRIBUTE permit 10
match ip add CUSTC
router ospf 100 vrf C
redistribute bgp 123 route-map CUSTC_REDISTRIBUTE subnets
hostname R8
int l0
ip add 8.8.8.8 255.255.255.255
int f0/0
no shut
ip add 192.168.18.8 255.255.255.0
router ospf 100
net 8.8.8.8 0.0.0.0 area 0
net 192.168.18.0 0.0.0.255 area 0
hostname R9
int l0
ip add 9.9.9.9 255.255.255.255
int f0/0
no shut
ip add 192.168.39.9 255.255.255.0
router ospf 100
net 9.9.9.9 0.0.0.0 area 0
net 192.168.39.0 0.0.0.255 area 0
Verification Link to heading
R1#show ip bgp vpnv4 all
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf A)
*> 4.4.4.4/32 192.168.14.4 0 32768 ?
*>i 5.5.5.5/32 3.3.3.3 0 100 0 ?
Route Distinguisher: 2:2 (default for vrf B)
*> 6.6.6.6/32 192.168.16.6 156160 32768 ?
*>i 7.7.7.7/32 3.3.3.3 156160 100 0 ?
*> 192.168.16.0 0.0.0.0 0 32768 ?
*>i 192.168.37.0 3.3.3.3 0 100 0 ?
Route Distinguisher: 3:3 (default for vrf C)
*> 8.8.8.8/32 192.168.18.8 2 32768 ?
*>i 9.9.9.9/32 3.3.3.3 2 100 0 ?
*> 192.168.18.0 0.0.0.0 0 32768 ?
*>i 192.168.39.0 3.3.3.3 0 100 0 ?
R8#show ip route ospf
9.0.0.0/32 is subnetted, 1 subnets
O IA 9.9.9.9 [110/3] via 192.168.18.1, 00:00:21, FastEthernet0/0
R8#ping 9.9.9.9 source 8.8.8.8
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 9.9.9.9, timeout is 2 seconds:
Packet sent with a source address of 8.8.8.8
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 544/750/924 ms
MPLS Traffic Engineering Link to heading
hostname R1
int l0
ip add 1.1.1.1 255.255.255.255
ip ospf 1 area 0
ip ospf net point-to-point
int f0/0
ip add 192.168.16.1 255.255.255.0
no shut
ip ospf 1 area 6
int f0/1
ip add 192.168.12.1 255.255.255.0
no shut
ip ospf 1 area 0
router ospf 1
area 6 stub no-sum
mpls label range 100 199
int f0/1
mpls ip
exit
mpls traffic-eng tunnels
router ospf 1
mpls traffic-eng router-id l0
mpls traffic-eng area 0
int f0/1
mpls traffic-eng tunnels
ip rsvp bandwidth 100000 100000
hostname R2
int l0
ip add 2.2.2.2 255.255.255.255
ip ospf 1 area 0
ip ospf net point-to-point
int f0/0
ip add 192.168.12.2 255.255.255.0
no shut
ip ospf 1 area 0
int f0/1
ip add 192.168.23.2 255.255.255.0
no shut
ip ospf 1 area 0
int f1/0
ip add 192.168.24.2 255.255.255.0
no shut
ip ospf 1 area 0
router ospf 1
mpls label range 200 299
int range f0/0-1,f1/0
mpls ip
exit
mpls traffic-eng tunnels
router ospf 1
mpls traffic-eng router-id l0
mpls traffic-eng area 0
int range f0/0-1,f1/0
mpls traffic-eng tunnels
ip rsvp bandwidth 100000 100000
hostname R3
int l0
ip add 3.3.3.3 255.255.255.255
ip ospf 1 area 0
ip ospf net point-to-point
int f0/0
ip add 192.168.23.3 255.255.255.0
no shut
ip ospf 1 area 0
int f0/1
ip add 192.168.34.3 255.255.255.0
no shut
ip ospf 1 area 0
router ospf 1
mpls label range 300 399
int range f0/0-1
mpls ip
exit
mpls traffic-eng tunnels
router ospf 1
mpls traffic-eng router-id l0
mpls traffic-eng area 0
int range f0/0-1
mpls traffic-eng tunnels
ip rsvp bandwidth 100000 100000
hostname R4
int l0
ip add 4.4.4.4 255.255.255.255
ip ospf 1 area 0
ip ospf net point-to-point
int f0/0
ip add 192.168.45.4 255.255.255.0
no shut
ip ospf 1 area 0
int f0/1
ip add 192.168.34.4 255.255.255.0
no shut
ip ospf 1 area 0
int f1/0
ip add 192.168.24.4 255.255.255.0
no shut
ip ospf 1 area 0
router ospf 1
mpls label range 400 499
int range f0/0-1,f1/0
mpls ip
exit
mpls traffic-eng tunnels
router ospf 1
mpls traffic-eng router-id l0
mpls traffic-eng area 0
int range f0/0-1,f1/0
mpls traffic-eng tunnels
ip rsvp bandwidth 100000 100000
hostname R5
int l0
ip add 5.5.5.5 255.255.255.255
ip ospf 1 area 0
ip ospf net point-to-point
int f0/0
ip add 192.168.57.5 255.255.255.0
no shut
ip ospf 1 area 7
int f0/1
ip add 192.168.45.5 255.255.255.0
no shut
ip ospf 1 area 0
router ospf 1
area 7 stub no-sum
mpls label range 500 599
int f0/1
mpls ip
exit
mpls traffic-eng tunnels
router ospf 1
mpls traffic-eng router-id l0
mpls traffic-eng area 0
int f0/1
mpls traffic-eng tunnels
ip rsvp bandwidth 100000 100000
Configure in R1 a tunnel R1 to R5 via R3
R1(config)#
ip explicit-path name VIA_P3 enable
index 10 next 2.2.2.2
index 20 next 3.3.3.3
index 30 next 4.4.4.4
index 40 next 5.5.5.5
int tunnel1
ip unnumbered Loopback0
tunnel mode mpls traffic-eng
tunnel destination 5.5.5.5
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng priority 3 3
tunnel mpls traffic-eng bandwidth 10000
tunnel mpls traffic-eng path-option 1 explicit name VIA_P3
Configure R6 and R7 in stub networks
hostname R6
int l0
ip add 6.6.6.6 255.255.255.255
ip ospf 1 area 6
ip ospf net point-to-point
int f0/0
ip add 192.168.16.6 255.255.255.0
ip ospf 1 area 6
no shut
router ospf 1
area 6 stub
hostname R7
int l0
ip add 7.7.7.7 255.255.255.255
ip ospf 1 area 7
ip ospf net point-to-point
int f0/0
ip add 192.168.57.7 255.255.255.0
ip ospf 1 area 7
no shut
router ospf 1
area 7 stub