Support for Static MPLS Labels on Cisco RSP3 Module

Feature History

Before Cisco IOS XE Bengaluru Release 17.5.1, pseudowires were dynamically provisioned using Label Distribution Protocol (LDP), or another directed control protocol such as Resource Reservation Protocol over traffic-engineered tunnels (RSVP-TE), to exchange the various parameters required for these connections. Starting with Cisco IOS XE Bengaluru Release 17.5.1, you can provision an Any Transport over Multiprotocol (AToM) label switching static pseudowire without the use of a directed control connection. In environments that do not or cannot use directed control protocols, a means for provisioning the pseudowire parameters statically at the Cisco IOS CLI is provided by the ATOM Static Pseudowire feature.

MPLS Static Feature Overview

The MPLS static feature enables static assignment of local labels to an IPv4 prefix per VRF. Label Switched Paths (LSPs) can be provisioned for these static labels by specifying the next-hop information required for forwarding packets with static labels.

Static labels offer advantages over dynamic labels:

• Improve security by reducing the risk of receiving unwanted labels from peers running a compromised MPLS dynamic labeling protocol.
• Provide full control over defined LSPs.
• Utilize system resources optimally as dynamic labeling is not processed.

Static Label Pseudowire Provisioning for CEM also overcomes the restriction of limited 1400 (1-dimensional) targeted LDP sessions scale. The feature allows manual configuration of the following parameters:

• Local Pseudowire Label
• Remote Pseudowire Label

This feature is supported on the following CEM IMs:

• 1-port OC-48 1/ STM-16 or 4-port OC-12/OC-3 / STM-1/STM-4 + 12-Port T1/E1 + 4-Port T3/E3 CEM Interface Module
• 1-port OC-192 Interface module or 8-port Low Rate Interface Module (ASR 900 Combo 8-port SFP GE and 1-port 10GE IM with CEM, 10G)
• 48-port T3/E3 CEM Interface Module
• 48-port T1/E1 CEM Interface Module
• NCS 4200 1-Port 10 Gigabit MR + 8-Port 20 Gigabit LR CEM, iMSG Interface Module

MPLS Label Range

The MPLS label range configuration helps define the dynamic label range. Labels falling outside this range are available for manual static allocation. The router does not verify statically configured labels against the specified dynamic range. To prevent label discrepancies, ensure static MPLS labels do not overlap with the dynamic label range.

Starting with Cisco IOS XE Bengaluru Release 17.5.1, the overall MPLS label range is from 16 through 32768. Both static and dynamic labels must be allocated within this range. For instance, if the dynamic label range is set from 16 through 32700, static labels can only be configured from 32701 through 32767.

The Cisco RSP3 module, as of Cisco IOS XE Bengaluru Release 17.5.1, supports 32k lookup labels or local labels. Increasing this scale requires increasing CEM pseudowires for both dynamic and static service labels. The MPLS label range must exceed 39k to maintain consistent configuration across pDCS (dynamic service labels) and pADM (static service labels).

To support 13k CEM PW protection, the requirement is 13440 for dynamic + 13440 for static + 10k global block + 2k SRLB/SRMS = 38880 total labels. To meet this requirement, the MPLS label range was extended from 32k to 40k starting with Cisco IOS XE Cupertino Release 17.7.1.

Configuring Static MPLS Labels on Cisco RSP3 Module

This section details the configuration of static MPLS labels on the Cisco RSP3 module for CEM. The diagram illustrates serial interfaces configured on Customer Edge (CE) routers (CE1 and CE2) and Xconnect configured on Provider Edge (PE) routers (PE1 and PE2). Unlike configurations using the LDP protocol for label assignment, static labels can be manually configured on PE1 and PE2 routers. CEM groups are also configured on these PE routers. Traffic originating from CE1 is sent to PE2, where packets are converted and forwarded to CE2.

Diagram Description: A network diagram showing four routers: CE1, PE1, PE2, and CE2. CE1 is connected to PE1 via a serial interface (2/1/0 to 0/7/4). PE1 is connected to PE2 via a gigabit interface (0/7/4 to 0/3/2). PE2 is connected to CE2 via a serial interface (0/3/2 to 3/0/0). The connections indicate the flow of traffic from CE1 through PE1 and PE2 to CE2.

The following configuration examples are for SONET VT-15 CEP mode.

Core Configuration

This section covers the core configuration, including loopback interfaces, MPLS label range, OSPF, and Segment Routing (SR) configurations. These configurations should be performed once at the beginning.

For PE1:

interface Loopback0
 no ip address
 ip address 10.1.1.1 255.0.0.0
end
l2 router-id 10.1.1.1
end
mpls label range 28032 32767 static 16 15998
mpls ldp label
 allocate global prefix-list DENYALL
 multilink bundle-name authenticated
end
segment-routing mpls
 global-block 16000 28031
 local-block 15999 15999
 connected-prefix-sid-map
  address-family ipv4
   10.1.1.1/32 absolute 16001 range 1
  exit-address-family
 end
no router ospf 100
end
router ospf 100
 router-id 10.1.1.1
 segment-routing area 0 mpls
  fast-reroute per-prefix enable prefix-priority high
  fast-reroute per-prefix ti-lfa
  fast-reroute keep-all-paths
 network 10.1.1.1 255.0.0.0 area 0
 network 192.168.1.0 255.255.0.0 area 0
end
interface Port-channel1
 ip address 192.168.1.1 255.255.0.0
 ip ospf network point-to-point
 ip ospf mtu-ignore
end
interface Te0/11/0
 no ip address
 cdp enable
 channel-group 1 mode active
end
network-clock input-source 1 interface Te0/11/0
network-clock synchronization automatic
network-clock synchronization mode qL-enabled
network-clock wait-to-restore 0 global
esmc process
end

For PE2:

interface Loopback0
 no ip address
 ip address 10.2.2.2 255.0.0.0
end
l2 router-id 10.2.2.2
end
mpls label range 28032 32767 static 16 15998
mpls ldp label
 allocate global prefix-list DENYALL
 multilink bundle-name authenticated
end
segment-routing mpls
 global-block 16000 28031
 local-block 15999 15999
 connected-prefix-sid-map
  address-family ipv4
   10.2.2.2/32 absolute 16002 range 1
  exit-address-family
 end
no router ospf 100
end
router ospf 100
 router-id 10.2.2.2
 segment-routing area 0 mpls
  fast-reroute per-prefix enable prefix-priority high
  fast-reroute per-prefix ti-lfa
  fast-reroute keep-all-paths
 network 10.2.2.2 255.0.0.0 area 0
 network 192.168.1.0 255.255.0.0 area 0
end
interface Port-channel1
 ip address 192.168.1.2 255.255.0.0
 ip ospf network point-to-point
 ip ospf mtu-ignore
end
interface Te0/4/0
 no ip address
 cdp enable
 channel-group 1 mode active
end
network-clock synchronization automatic
network-clock synchronization mode qL-enabled
esmc process
end

Controller Configuration

This section shows the controller configuration of the routers.

For CE 1:

controller sonet 2/1/0
 framing sonet
end
controller sonet 2/1/0
 no shut
end
controller sonet 2/1/0
sts-1 1
 mode vt-15
 vtg 1 t1 1 channel-group 0 timeslots 1-24
end
interface Serial2/1/0.1/1/1:0
 ip address 172.16.0.1 255.240.0.0
end

For PE1:

controller mediatype 0/7/4
 mode sonet
controller sonet 0/7/4
 rate OC12
end
controller sonet 0/7/4
sts-1 1
 mode vt-15
 vtg 1 vt 1 cem-group 0 cep
end

For PE2:

controller mediatype 0/3/2
 mode sonet
controller sonet 0/3/2
 rate OC12
end
controller sonet 0/3/2
sts-1 1
 mode vt-15
 vtg 1 vt 1 cem-group 0 cep
end

For CE 2:

controller sonet 3/0/0
 framing sonet
end
controller sonet 3/0/0
 no shut
end
controller sonet 3/0/0
sts-1 1
 mode vt-15
 vtg 1 t1 1 channel-group 0 timeslots 1-24
end
interface Serial3/0/0.1/1/1:0
 ip address 172.16.0.2 255.240.0.0
end

Verification of Static Label Pseudowire Provisioning for CEM Configuration

Xconnect Configuration

This section shows the Xconnect configuration of PE1 and PE2 routers.

For PE1:

interface cem 0/7/4
cem 0
 xconnect 10.2.2.2 1 encapsulation mpls manual
 mpls label 16 16
end
interface cem 0/7/4
cem 1
 xconnect 10.2.2.2 2 encapsulation mpls manual
 mpls label 17 17
end

For PE2:

interface cem 0/3/2
cem 0
 xconnect 10.1.1.1 1 encapsulation mpls manual
 mpls label 16 16
end
interface cem 0/3/2
cem 1
 xconnect 10.1.1.1 2 encapsulation mpls manual
 mpls label 17 17
end

Verification Steps

Use the following commands to verify the MPLS label configuration and virtual connection (VC) details.

Verify MPLS Label Configuration:

Use the show run | i mpls label command to verify the MPLS label configuration.

Router# show run | i mpls label
mpls label range 16 32700 static 32701 32767
interface CEM0/4/2
 no ip address
 cem 0
 xconnect 10.3.3.3 1 encapsulation mpls manual
 mpls label 32702 32702

Verify Virtual Connection (VC) Details:

Use the show mpls l2 vc vc-id detail command to display detailed information related to the virtual connection (VC) with the signaling protocol manual configuration.

Router# show mpls l2 vc 1 detail
Local interface: CE0/4/2 up, line protocol up, SATOP T1 0 up
Destination address:10.3.3.3, VC ID:1 , VC status: up
Output interface: Po1, imposed label stack {16005 32702}
Preferred path: not configured
Default path: active
Next hop: 10.10.1.6
Create time: 00:00:54, last status change time: 00:00:54
Last label FSM state change time: 00:00:54
Signaling protocol: Manual
Status TLV support (local/remote) : enabled/N/A
LDP route watch : enabled
Label/status state machine : established, LruRru
Last local dataplane status rcvd: No fault
Last BFD dataplane status rcvd: Not sent
Last BFD peer monitor status rcvd: No fault
Last local AC circuit status rcvd: No fault
Last local AC circuit status sent: No fault
Last local PW i/f circ status rcvd: No fault
Last local LDP TLV status sent: No status
Last remote LDP TLV status rcvd: Not sent
Last remote LDP ADJ status rcvd: No fault
MPLS VC labels: local 32702, remote 32702
Group ID: local 498, remote 498
MTU: local 0, remote 0
Sequencing: receive disabled, send disabled
Control Word: On (configured: autosense)
SSO Descriptor: 209.165.201.5/40004010, local label: 32702
Dataplane:
SSM segment/switch IDs: 12313/16408 (used), PWID: 2
VC statistics:
transit packet totals: receive 0, send 0
transit byte totals: receive 0, send 0
transit packet drops: receive 0, seq error 0, send 0

Use the show run | sec pseudowire99 and show run | sec l2vpn commands to verify the MPLS label configuration with L2VPN Xconnect.

Router#show run | sec pseudowire99
interface pseudowire99
 encapsulation mpls
 signaling protocol none
 neighbor 10.1.1.1 1
  label 27001 27001

Router#show run | sec l2vpn
l2vpn xconnect context cem_static
 member CEM0/3/0 0
 member pseudowire99

Use the show mpls l2 vc vc-id detail command to display detailed information related to the virtual connection (VC) with the signaling protocol manual configuration.

Router# show mpls l2 vc 1 detail
Local interface: CE0/3/0 up, line protocol up, SATOP T1 0 up
Destination address: 10.1.1.1, VC ID: 1, VC status: down
Last error: MPLS dataplane reported a fault to the nexthop
Output interface: none, imposed label stack {}
Preferred path: not configured
Default path: no route
No adjacency
Create time: 00:04:40, last status change time: 00:04:40
Last label FSM state change time: 00:04:40
Signaling protocol: Manual
Status TLV support (local/remote) : enabled/N/A
LDP route watch : enabled
Label/status state machine : activating, LruRruD
Last local dataplane status rcvd: DOWN(pw-tx-fault)
Last BFD dataplane status rcvd: Not sent
Last BFD peer monitor status rcvd: No fault
Last local AC circuit status rcvd: No fault
Last local AC circuit status sent: DOWN(pw-rx-fault)
Last local PW i/f circ status rcvd: No fault
Last local LDP TLV status sent: No status
Last remote LDP TLV status rcvd: Not sent
Last remote LDP ADJ status rcvd: No fault
MPLS VC labels: local 27001, remote 27001
Group ID: local 94, remote 94
MTU: local 0, remote 0
Sequencing: receive disabled, send disabled
Control Word: On (configured: autosense)
SSO Descriptor: 10.1.1.1/1, local label: 27001
Dataplane:
SSM segment/switch IDs: 0/20492 (used), PWID: 5
VC statistics:
transit packet totals: receive 0, send 0
transit byte totals: receive 0, send 0
transit packet drops: receive 0, seq error 0, send 0