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The MPLS—Multilink PPP Support feature ensures that MPLS Layer 3 Virtual Private Networks (VPNs) with quality of service (QoS) can be enabled for bundled links. This feature supports Multiprotocol Label Switching (MPLS) over Multilink PPP (MLP) links in the edge (provider edge [PE]-to-customer edge [CE]) or in the MPLS core (PE-to-PE and PE-to-provider router [P]).
Service providers that use relatively low-speed links can use MLP to spread traffic across them in their MPLS networks. Link fragmentation and interleaving (LFI) should be deployed in the CE-to-PE link for efficiency, where traffic uses a lower link bandwidth (less than 768 kbps).
Finding Feature Information in This Module
Your Cisco IOS software release may not support all of the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for MPLS—Multilink PPP Support" section.
Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images
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•Prerequisites for MPLS—Multilink PPP Support
•Restrictions for MPLS—Multilink PPP Support
•Information About MPLS—Multilink PPP Support
•How to Configure MPLS—Multilink PPP Support
•Configuration Examples for MPLS—Multilink PPP Support
•Feature Information for MPLS—Multilink PPP Support
The MPLS—Multilink PPP Support feature requires the following:
•Cisco Express Forwarding or distributed Cisco Express Forwarding enabled
•MPLS enabled on PE and P routers
•Cisco Express Forwarding switching enabled on the interface with the ip route-cache cef command
Table 1 lists the required port adapters and processors for the MPLS—Multilink PPP Support feature on the Cisco 7200 series routers. Table 2 lists the required port adapters and processors for the MPLS—Multilink PPP Support feature on the Cisco 7500 series routers.
The MPLS—Multilink PPP Support feature is limited byplatform-specific restrictions that apply to the use of MLP and distributed MLP (dMLP).
For restrictions that apply to dMLP on the Cisco 7500 routers, see the Distributed Multilink Point-to-Point Protocol for Cisco 7500 Series Routers feature module.
This section contains information that you need to use the MPLS—Multilink PPP Support feature:
•MPLS Features Supported for Multilink PPP
•MPLS—Multilink PPP Support and PE-to-CE Links
•MPLS—Multilink PPP Support and Core Links
•MPLS—Multilink PPP Support in a CSC Network
•MPLS—Multilink PPP Support in an Interautonomous System
The following topics provide information about MPLS features supported for MLP:
•MPLS Layer 3 Virtual Private Network Features Supported for Multilink PPP
•MPLS Quality of Service Features Supported for Multilink PPP
Table 3 lists MPLS Layer 3 VPN features supported for MLP and indicates if the feature is supported on CE-to-PE links, PE-to-P links, and Carrier Supporting Carrier (CSC) CE-to-PE links.
|
|
|
|
---|---|---|---|
Static routes |
Supported |
—1 |
— |
External Border Gateway Protocol (eBGP) |
Supported |
Not applicable to this configuration |
Supported |
Intermediate System-to-Intermediate System (IS-IS) |
— |
Supported |
— |
Open Shortest Path first (OSPF) |
Supported |
Supported |
— |
Enhanced Interior Gateway Routing Protocol (EIGRP) |
Supported |
Supported |
— |
Interprovider (Inter-AS) VPNs (with Label Distribution Protocol [LDP]) |
Not applicable to this configuration |
Supported (MLP between Autonomous System Border routers {ASBRs]) |
Not applicable to this configuration |
Inter-AS VPNs with IPv4 Label Distribution |
Not applicable to this configuration |
Supported (MLP between ASBRs] |
Not applicable to this configuration |
CSC VPNs (with LDP) |
— |
Not applicable to this configuration |
Supported |
CSC VPNs with IPv4 label distribution |
Supported |
Not applicable to this configuration |
Supported |
External and internal BGP (eiBGP) Multipath |
— |
— |
Not applicable to this configuration |
Internal BGP (iBGP) Multipath |
Not applicable to this configuration |
— |
Not applicable to this configuration |
eBGP Multipath |
— |
— |
— |
1 An em dash (—) indicates that the configuration is not supported. |
Table 4 lists the MPLS QoS features supported for MLP and indicates if the feature is supported on CE-to-PE links, PE-to-P links, and CSC-CE-to-CSC-PE links.
|
|
|
|
---|---|---|---|
Default copy of IP Precedence to EXP bits and the reverse |
Supported |
—1 |
— |
Set MPLS EXP bits using the modular QoS Command Line Interface (MQC) |
Supported |
Supported |
Supported |
Matching on MPLS EXP using MQC |
Supported |
Supported |
Supported |
Low Latency Queueing (LLQ)/ |
Supported |
Supported |
Supported |
Weighted Random Early Detection (WRED) based on EXP bits using MQC |
Supported |
Supported |
Supported |
Policer with EXP bit-marking using MQC-3 action |
Supported |
Supported |
Supported |
Support for EXP bits in MPLS accounting |
Supported |
Supported |
Supported |
1 An em dash (—) indicates that the configuration is not supported. |
Figure 1 shows a typical MPLS network in which the PE router is responsible for label imposition (at ingress) and disposition (at egress) of the MPLS traffic.
In this topology, MLP is deployed on the PE-to-CE links. The VPN routing and forwarding instance (VRF) interface is in a multilink bundle. There is no MPLS interaction with MLP; all packets coming into the MLP bundle are IP packets.
Figure 1 MLP and Traditional PE-to-CE Links
The PE-to-CE routing protocols that are supported for the MPLS—Multilink PPP Support feature are eBGP, OSPF, and EIGRP. Static routes are also supported between the CE and PE routers.
QoS features that are supported for the MPLS—Multilink PPP Support feature on CE-to-PE links are LFI, compressed Real-Time Transport Protocol (cRTP), policing, marking, and classification.
Figure 2 shows a sample topology in which MPLS is deployed over MLP on PE-to-P and P-to-P links. Enabling MPLS on MLP for PE-to-P links is similar to enabling MPLS on MLP for P-to-P links.
Figure 2 MLP on PE-to-P and P-to-P Links
You employ MLP in the PE-to-P or P-to-P links primarily so that you can reduce the number of Interior Gateway Protocol (IGP) adjacencies and facilitate the load sharing of traffic.
In addition to requiring MLP on the PE-to-P links, the MPLS—Multilink PPP Support feature requires the configuration of an IGP routing protocol and LDP.
Figure 3 shows a typical MPLS VPN CSC network where MLP is configured on the CSC-CE-to-CSC-PE links.
Figure 3 MLP on CSC-CE-to-CSC-PE Links with MPLS VPN Carrier Supporting Carrier
The MPLS—Multilink PPP Support feature supports MLP between CSC-CE and CSC-PE links with LDP or with EBGP IPv4 label distribution. This feature also supports LFI for an MPLS VPN CSC configuration. Figure 4 shows all MLP links that this feature supports for CSC configurations.
Figure 4 MLP Supported Links with MPLS VPN Carrier Supporting Carrier
Figure 5 shows a typical MPLS VPN interautonomous system (Inter-AS) network where MLP is configured on the PE-to-CE links.
Figure 5 MLP on ASBR-to-PE Links in an MPLS VPN Inter-AS Network
The MPLS—Multilink PPP Support feature supports MLP between ASBR links for Inter-AS VPNs with LDP and with eBGP IPv4 label distribution.
This section contains the following procedures for configuring the MPLS—Multilink PPP Support feature:
•Enabling Cisco Express Forwarding or Distributed Cisco Express Forwarding Switching (required)
•Creating a Multilink Bundle for MPLS—Multilink PPP Support (required)
•Assigning an Interface to a Multilink Bundle for MPLS—Multilink PPP Support (required)
•Disabling PPP Multilink Fragmentation (optional)
•Verifying the Multilink PPP Configuration (optional)
Service providers that use relatively low-speed links can use MLP to spread traffic across them in their MPLS networks. LFI should be deployed in the CE-to-PE link for efficiency, where traffic uses lower link bandwidth (less than 768 kbps). The MPLS—Multilink PPP Support feature can reduce the number of IGP adjacencies and facilitate load sharing of traffic.
The tasks in this section can be performed on CE-to-PE links, PE-to-P links, P-to-P links, and CSC CSC-CE-to-CSC-PE links.
Perform the following task to enable Cisco Express Forwarding or distributed Cisco Express Forwarding switching. Cisco Express Forwarding or distributed Cisco Express Forwarding is required for the forwarding of MLP or dMLP traffic.
Multilink PPP requires the configuration of standard Cisco Express Forwarding. Distributed MLP (dMLP) requires the configuration of distributed Cisco Express Forwarding.
Cisco Express Forwarding is enabled by default on most Cisco platforms running Cisco IOS software Release12.0 or a later release. To find out if Cisco Express Forwarding is enabled on your platform, enter the show ip cef command. If Cisco Express Forwarding is enabled, you receive output that looks like this:
Router# show ip cef
Prefix Next Hop Interface
10.2.61.8/24 192.168.100.1 FastEthernet1/0/0
192.168.101.1 FastEthernet6/1
If Cisco Express Forwarding is not enabled on your platform, the output for the show ip cef command looks like this:
Router# show ip cef
%CEF not running
Distributed Cisco Express Forwarding is enabled by default on devices such as the Catalyst 6500 series switch, the Cisco 7500 series router, and the Cisco 12000 series Internet router.
1. enable
2. configure terminal
3. ip cef
or
ip cef distributed
4. exit
Perform this task to create a multilink bundle for the MPLS—Multilink PPP Support feature. This can reduce the number of IGP adjacencies and facilitate load sharing of traffic.
1. enable
2. configure terminal
3. interface multilink group-number
4. ip address address mask [secondary]
5. encapsulation encapsulation-type
6. ppp multilink
7. end
Perform this task to assign an interface to a multilink bundle for the MPLS—Multilink PPP Support feature.
1. enable
2. configure terminal
3. controller {t1 | e1} slot/port
4. channel-group channel-number timeslots range
5. exit
6. interface serial slot/port:channel-group
7. ip route-cache [cef |distributed]
8. no ip address
9. keepalive [period [retries]]
10. encapsulation encapsulation-type
11. multilink-group group-number
12. ppp multilink
13. ppp authentication chap
14. end
Perform this task to disable PPP multilink fragmentation. PPP multilink fragmentation is enabled by default.
Enabling fragmentation reduces the delay latency among bundle links, but adds some load to the CPU. Disabling fragmentation might produce better throughput.
If your data traffic is consistently of a similar size, we recommend disabling fragmentation. In this case, the benefits of fragmentation can be outweighed by the added load on the CPU.
Distributed MLP over MPLS does not support fragmentation of the packets, unless you enable LFI on the MLP interface using the following commands:
Router(config)# interface multilink group-number
Router(config-if)# ppp multilink interleave
Router(config-if)# ppp multilink fragment-delay milliseconds
1. enable
2. configure terminal
3. interface type number
4. ppp multilink fragmentation disable
5. end
Perform the following task to verify the Multilink PPP configuration.
1. enable
2. show ip interface brief
3. show ppp multilink
4. show ppp multilink interface interface-bundle
5. show interface interface-name interface-number
6. show mpls forwarding-table
7. exit
Step 1 enable
Use this command to enable privileged EXEC mode. Enter your password if prompted. For example:
Router> enable
Router#
Step 2 show ip interface brief
Use this command to verify logical and physical MLP interfaces. For example:
Router# show ip interface brief
Locolrface IP-Address OK? Method Status Prot
Ethernet0/0/0 10.3.62.106 YES NVRAM up up
Ethernet0/0/1 unassigned YES NVRAM administratively down down
Ethernet0/0/2 unassigned YES NVRAM administratively down down
Ethernet0/0/3 unassigned YES NVRAM administratively down down
Ethernet0/0/4 unassigned YES NVRAM administratively down down
Ethernet0/0/5 unassigned YES NVRAM administratively down down
Ethernet0/0/6 unassigned YES NVRAM administratively down down
Ethernet0/0/7 unassigned YES NVRAM administratively down down
Ethernet0/1/0 unassigned YES NVRAM administratively down down
Ethernet0/1/1 unassigned YES NVRAM administratively down down
Ethernet0/1/2 unassigned YES NVRAM administratively down down
Ethernet0/1/3 unassigned YES NVRAM administratively down down
Ethernet0/1/4 unassigned YES NVRAM administratively down down
Ethernet0/1/5 unassigned YES NVRAM administratively down down
Ethernet0/1/6 unassigned YES NVRAM administratively down down
Ethernet0/1/7 unassigned YES NVRAM administratively down down
Serial1/1/0:1 unassigned YES NVRAM administratively down down
Serial1/1/0:2 unassigned YES NVRAM administratively down down
Serial1/1/1:1 unassigned YES NVRAM up up
Serial1/1/1:2 unassigned YES NVRAM up down
Serial1/1/3:1 unassigned YES NVRAM up up
Serial1/1/3:2 unassigned YES NVRAM up up
Multilink6 10.30.0.2 YES NVRAM up up
Multilink8 unassigned YES NVRAM administratively down down
Multilink10 10.34.0.2 YES NVRAM up up
Loopback0 10.0.0.1 YES NVRAM up up
Step 3 show ppp multilink
Use this command to verify that you have created a multilink bundle. For example:
Router# show ppp multilink
Multilink1, bundle name is group 1
Bundle is Distributed
0 lost fragments, 0 reordered, 0 unassigned, sequence 0x0/0x0 rcvd/sent
0 discarded, 0 lost received, 1/255 load
Member links: 4 active, 0 inactive (max no set, min not set)
Serial1/0/0/:1
Serial1/0/0/:2
Serial1/0/0/:3
Serial1/0/0/:4
Step 4 show ppp multilink interface interface-bundle
Use this command to display information about a specific MLP interface. For example:
Router# show ppp multilink interface multilink6
Multilink6, bundle name is router
Bundle up for 00:42:46, 1/255 load
Receive buffer limit 24384 bytes, frag timeout 1524 ms
Bundle is Distributed
0/0 fragments/bytes in reassembly list
1 lost fragments, 48 reordered
0/0 discarded fragments/bytes, 0 lost received
0x4D7 received sequence, 0x0 sent sequence
Member links: 2 active, 0 inactive (max not set, min not set)
Se1/1/3:1, since 00:42:46, 240 weight, 232 frag size
Se1/1/3:2, since 00:42:46, 240 weight, 232 frag size
dLFI statistics:
DLFI Packets Pkts In Chars In Pkts Out Chars Out
Fragmented 86 13072 86 12857
UnFragmented 1144 85502 1091 82208
Reassembled 1187 98230 1134 94721
Reassembly Drops 0
Fragmentation Drops 0
Out of Seq Frags 1
Note On Cisco 7500 routers, distributed LFI statistics are displayed only if LFI is enabled on a distributed MLP interface.
Step 5 show interface interface-name interface-number
Use this command to display information about serial interfaces in your configuration. For example:
Router# show interface serial 1/1/3:1
Serial1/1/3:1 is up, line protocol is up
Hardware is Multichannel T1
MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open, multilink Open, crc 16, Data non-inverted
Last input 00:00:01, output 00:00:01, output hang never
Last clearing of "show interface" counters 00:47:13
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
722 packets input, 54323 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
697 packets output, 51888 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 output buffer failures, 0 output buffers swapped out
1 carrier transitions no alarm present
Timeslot(s) Used:1, subrate: 64Kb/s, transmit delay is 0 flags
Transmit queue length 25
Router# show interface serial 1/1/3:2
Serial1/1/3:2 is up, line protocol is up
Hardware is Multichannel T1
MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open, multilink Open, crc 16, Data non-inverted
Last input 00:00:03, output 00:00:03, output hang never
Last clearing of "show interface" counters 00:47:16
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
725 packets input, 54618 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
693 packets output, 53180 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 output buffer failures, 0 output buffers swapped out
1 carrier transitions no alarm present
Timeslot(s) Used:2, subrate: 64Kb/s, transmit delay is 0 flags
Transmit queue length 26
You can also use the show interface command to display information about the multilink interface:
Router# show interface multilink6
Multilink6 is up, line protocol is up
Hardware is multilink group interface
Internet address is 10.30.0.2/8
MTU 1500 bytes, BW 128 Kbit, DLY 100000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open, multilink Open
Open: CDPCP, IPCP, TAGCP, loopback not set
DTR is pulsed for 2 seconds on reset
Last input 00:00:00, output never, output hang never
Last clearing of "show interface" counters 00:48:43
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
30 second input rate 0 bits/sec, 0 packets/sec
30 second output rate 0 bits/sec, 0 packets/sec
1340 packets input, 102245 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
1283 packets output, 101350 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
Step 6 show mpls forwarding-table
Use this command to display contents of the MPLS Label Forwarding Information Base (LFIB) and look for information on multilink interfaces associated with a point2point next hop. For example:
Router# show mpls forwarding-table
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
16 Untagged 10.30.0.1/32 0 Mu6 point2point
17 Pop tag 10.0.0.3/32 0 Mu6 point2point
18 Untagged 10.0.0.9/32[V] 0 Mu10 point2point
19 Untagged 10.0.0.11/32[V] 6890 Mu10 point2point
20 Untagged 10.32.0.0/8[V] 530 Mu10 point2point
21 Aggregate 10.34.0.0/8[V] 0
22 Untagged 10.34.0.1/32[V] 0 Mu10 point2point
Use the show ip bgp vpnv4 command to display VPN address information from the Border Gateway Protocol (BGP) table:
Router# show ip bgp vpnv4 all summary
BGP router identifier 10.0.0.1, local AS number 100
BGP table version is 21, main routing table version 21
10 network entries using 1210 bytes of memory
10 path entries using 640 bytes of memory
2 BGP path attribute entries using 120 bytes of memory
1 BGP extended community entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 1994 total bytes of memory
BGP activity 10/0 prefixes, 10/0 paths, scan interval 5 secs
10.0.0.3 4 100 MsgRc52 MsgSe52 TblV21 0 0 00:46:35 State/P5xRcd
Step 7 exit
Use this command to exit to user EXEC mode. For example:
Router# exit
Router>
The following are configuration examples for the MPLS—Multilink PPP Support feature:
•Sample MPLS—Multilink PPP Support Configurations
•Enabling Cisco Express Forwarding or Distributed Cisco Express Forwarding: Example
•Creating a Multilink Bundle for MPLS—Multilink PPP Support: Example
•Assigning an Interface to a Multilink Bundle for MPLS—Multilink PPP Support: Example
The following examples show sample configurations for MLP on a Cisco 7200 router, on a Cisco 7500 router, and on a CSC network. The configuration of MLP on an interface is the same for PE-to-CE links, PE-to-P links, and P-to-P links.
•Sample Multilink PPP Configuration on a Cisco 7200 Series Router
•Sample Multilink PPP Configuration for a Cisco 7500 Series Router
•Sample Multilink PPP Configuration on an MPLS CSC PE Router
Following is a sample configuration of a Cisco 7200 router, which is connected with a T1 line card and configured with an MPLS Multilink PPP interface:
controller T1 1/3
framing esf
clock source internal
linecode b8zs
channel-group 1 timeslots 1
channel-group 2 timeslots 2
no yellow generation
no yellow detection
!
interface Multilink6
ip address 10.37.0.1 255.0.0.0
ppp multilink interleave
tag-switching ip
load-interval 30
multilink-group 6
!
interface Serial1/3:1
encapsulation ppp
no ip address
ppp multilink
tx-queue-limit 26
multilink-group 6
peer neighbor-route
!
interface Serial1/3:2
encapsulation ppp
no ip address
ppp multilink
tx-queue-limit 26
multilink-group 6
peer neighbor-route
Following is a sample configuration of a Cisco 7500 router, which is connected with a T1 line card and configured with an MPLS Multilink PPP interface:
controller T1 1/1/3
framing esf
clock source internal
linecode b8zs
channel-group 1 timeslots 1
channel-group 2 timeslots 2
no yellow generation
no yellow detection
!
interface Multilink6
ip address 10.37.0.2 255.0.0.0
ppp multilink interleave
tag-switching ip
load-interval 30
multilink-group 6
!
interface Serial1/1/3:1
encapsulation ppp
no ip address
ppp multilink
tx-queue-limit 26
multilink-group 6
peer neighbor-route
!
interface Serial1/1/3:2
encapsulation ppp
no ip address
ppp multilink
tx-queue-limit 26
multilink-group 6
peer neighbor-route
Following is a sample configuration for an MPLS CSC PE router. An eBGP session is configured between the PE and CE routers.
PE-Router# show running-config interface Serial1/0:1
Building configuration...
!
mpls label protocol ldp
ip cef
ip vrf vpn2
rd 200:1
route-target export 200:1
route-target import 200:1
!
controller T1 1/0
framing esf
clock source internal
linecode b8zs
channel-group 1 timeslots 1
channel-group 2 timeslots 2
no yellow generation
no yellow detection
!
interface Serial1/0:1
no ip address
encapsulation ppp
tx-ring-limit 26
ppp multilink
ppp multilink group 1
!
interface Serial1/0:2
no ip address
encapsulation ppp
tx-ring-limit 26
ppp multilink
ppp multilink group 1
!
interface Multilink1
ip vrf forwarding vpn2
ip address 10.35.0.2 255.0.0.0
no peer neighbor-route
load-interval 30
ppp multilink
ppp multilink interleave
ppp multilink group 1
!
!
router ospf 200
log-adjacency-changes
auto-cost reference-bandwidth 1000
redistribute connected subnets
passive-interface Multilink1
network 10.0.0.7 0.0.0.0 area 200
network 10.31.0.0 0.255.255.255 area 200
!
!
router bgp 200
no bgp default ipv4-unicast
bgp log-neighbor-changes
neighbor 10.0.0.11 remote-as 200
neighbor 10.0.0.11 update-source Loopback0
!
address-family vpnv4
neighbor 10.0.0.11 activate
neighbor 10.0.0.11 send-community extended
bgp scan-time import 5
exit-address-family
!
address-family ipv4 vrf vpn2
redistribute connected
neighbor 10.35.0.1 remote-as 300
neighbor 10.35.0.1 activate
neighbor 10.35.0.1 as-override
neighbor 10.35.0.1 advertisement-interval 5
no auto-summary
no synchronization
exit-address-family
The following example shows how to enable Cisco Express Forwarding for MLP configurations:
enable
configure terminal
ip cef
The following example shows how to enable distributed Cisco Express Forwarding for dMLP configurations:
enable
configure terminal
ip cef distributed
The following example shows how to create a multilink bundle for the MPLS—Multilink PPP Support feature:
interface multilink 1
ip address 10.0.0.0 10.255.255.255
encapsulation ppp
ppp chap hostname group 1
ppp multilink
multilink-group 1
The following example shows how to create four multilink interfaces with distributed Cisco Express Forwarding switching and MLP enabled. Each of the newly created interfaces is added to a multilink bundle for the MPLS—Multilink PPP Support feature.
interface multilink 1
ip address 10.0.0.0 10.255.255.255
ppp chap hostname group 1
ppp multilink
multilink-group 1
interface serial 1/0/0/:1
no ip address
encapsulation ppp
ip route-cache distributed
no keepalive
ppp multilink
multilink-group 1
interface serial 1/0/0/:2
no ip address
encapsulation ppp
ip route-cache distributed
no keepalive
ppp chap hostname group 1
ppp multilink
multilink-group 1
interface serial 1/0/0/:3
no ip address
encapsulation ppp
ip route-cache distributed
no keepalive
ppp chap hostname group 1
ppp multilink
multilink-group 1
interface serial 1/0/0/:4
no ip address
encapsulation ppp
ip route-cache distributed
no keepalive
ppp chap hostname group 1
ppp multilink
multilink-group
The following sections provide references related to the MPLS—Multilink PPP Support feature:
|
|
---|---|
Configuration tasks for distributed MLP for Cisco 7500 series routers |
Distributed Multilink Point-to-Point Protocol for Cisco 7500 Series Routers |
Configuration tasks for media-independent PPP and Multilink PPP |
|
Configuration tasks for MPLS DiffServ tunneling modes |
|
Configuration tasks for the MPLS QoS multi-VC mode feature |
Configuring MPLS" chapter, Cisco IOS Multiprotocol Label Switching Configuration Guide |
Configuration tasks for MPLS VPNs |
"MPLS Virtual Private Networks" chapter, Cisco IOS Multiprotocol Label Switching Configuration Guide |
Configuration tasks for MPLS VPN CSC |
"MPLS Virtual Private Networks" chapter, Cisco IOS Multiprotocol Label Switching Configuration Guide |
Configuration tasks for MPLS VPN CSC with IPv4 BGP label distribution |
"MPLS Virtual Private Networks" chapter, Cisco IOS Multiprotocol Label Switching Configuration Guide |
Configuration tasks for MPLS VPN Inter-AS with IPv4 BGP label distribution |
"MPLS Virtual Private Networks" chapter, Cisco IOS Multiprotocol Label Switching Configuration Guide |
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No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
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RFC 1990 |
The PPP Multilink Protocol (MP) |
This feature uses no new or modified commands.
Table 5 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.
Note Table 5 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.
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MPLS—Multilink PPP Support |
12.2(8)T |
The MPLS—Multilink PPP Support feature ensures that MPLS Layer 3 Virtual Private Networks (VPNs) with quality of service (QoS) can be enabled for bundled links. This feature supports Multiprotocol Label Switching (MPLS) over Multilink PPP (MLP) links in the edge (provider edge [PE]-to-customer edge [CE]) or in the MPLS core (PE-to-PE and PE-to-provider router [P]). Service providers that use relatively low-speed links can use MLP to spread traffic across them in their MPLS networks. Link fragmentation and interleaving (LFI) should be deployed in the CE-to-PE link for efficiency, where traffic uses a lower link bandwidth (less than 768 kbps). In 12.2(8)T, MLP support on CE-to-PE links was introduced. In 12.2(15)T10 and 12.3(5a), MLP support for MPLS networks was extended to PE-to-P links, PE-to-PE links, Carrier Supporting Carrier (CSC) CSC-CE-to-CSC-PE links, and interautonomous system (Inter-AS) PE-to-PE links. In 12.3(7)T, the feature was integrated into the Cisco IOS 12.3T release. In 12.2(28)SB, the feature was integrated into the Cisco IOS 12.2SB release. In 12.4(20)T, the feature was integrated into the Cisco IOS 12.4T release. |
The following sections provide information about this feature: •MPLS Features Supported for Multilink PPP •MPLS—Multilink PPP Support and PE-to-CE Links •MPLS—Multilink PPP Support and PE-to-CE Links •MPLS—Multilink PPP Support and Core Links •MPLS—Multilink PPP Support in a CSC Network •MPLS—Multilink PPP Support in an Interautonomous System •Enabling Cisco Express Forwarding or Distributed Cisco Express Forwarding Switching •Creating a Multilink Bundle for MPLS—Multilink PPP Support •Assigning an Interface to a Multilink Bundle for MPLS—Multilink PPP Support •Disabling PPP Multilink Fragmentation |
bundle—A group of interfaces connected by parallel links between two systems that have agreed to use Multilink PPP (MLP) over those links.
CBWFQ—class-based weighted fair queueing. A queueing option that extends the standard Weighted Fair Queueing (WFQ) functionality to provide support for user-defined traffic classes.
Cisco Express Forwarding—A proprietary form of switching that optimizes network performance and scalability for networks with large and dynamic traffic patterns, such as the Internet, and for networks characterized by intensive web-based applications or interactive sessions. Although you can use Cisco Express Forwarding in any part of a network, it is designed for high-performance, highly resilient Layer 3 IP backbone switching.
EIGRP—Enhanced Interior Gateway Routing Protocol. An advanced version of the Interior Gateway Routing Protocol (IGRP) developed by Cisco. It provides superior convergence properties and operating efficiency, and combines the advantages of link-state protocols with those of distance vector protocols.
IGP—Interior Gateway Protocol. An Internet protocol used to exchange routing information within an autonomous system. Examples of common Internet IGPs include Interior Gateway Routing Protocol (IGRP), Open Shortest Path First (OSPF), and Routing Information Protocol (RIP).
IGRP—Interior Gateway Routing Protocol. An Interior Gateway Protocol (IGP) developed by Cisco to address the issues associated with routing in large, heterogeneous networks. Compare with Enhanced Interior Gateway Routing Protocol (EIGRP).
IS-IS—Intermediate System-to-Intermediate System. An Open Systems Interconnection (OSI) link-state hierarchical routing protocol, based on DECnet Phase V routing, in which IS-IS routers exchange routing information based on a single metric to determine network topology.
LCP—Link Control Protocol. A protocol that establishes, configures, and tests data link connections for use by PPP.
LFI—link fragmentation and interleaving. The Cisco IOS LFI feature reduces delay on slower-speed links by breaking up large datagrams and interleaving low-delay traffic packets with the smaller packets resulting from the fragmented datagram. LFI allows reserve queues to be set up so that Real-Time Protocol (RTP) streams can be mapped into a higher priority queue in the configured weighted fair queue set.
link—One of the interfaces in a bundle.
LLQ—low latency queueing. A quality of service QoS queueing feature that provides a strict priority queue (PQ) for voice traffic and weighted fair queues for other classes of traffic. It is also called priority queueing/class-based weighted fair queueing (PQ/CBWFQ).
MLP—Multilink PPP. A method of splitting, recombining, and sequencing datagrams across multiple logical links. The use of MLP increases throughput between two sites by grouping interfaces and then load balancing packets over the grouped interfaces (called a bundle). Splitting packets at one end, sending them over the bundled interfaces, and recombining them at the other end achieves load balancing.
MQC—Modular QoS CLI. MQC is a CLI structure that allows users to create traffic polices and attach these polices to interfaces. MQC allows users to specify a traffic class independently of QoS policies.
NCP—Network Control Protocol. A series of protocols for establishing and configuring different network layer protocols (such as for AppleTalk) over PPP.
OSPF—Open Shortest Path First. A link-state, hierarchical Interior Gateway Protocol (IGP) routing algorithm proposed as a successor to Routing Information Protocol (RIP) in the Internet community. OSPF features include least-cost routing, multipath routing, and load balancing. OSPF was derived from an early version of the IS-IS protocol.
PPP—Point-to-Point Protocol. A successor to the Serial Line Interface Protocol (SLIP) that provides router-to-router and host-to-network connections over synchronous and asynchronous circuits. PPP works with several network layer protocols (such as IP, Internetwork Packet Exchange [IPX], and AppleTalk Remote Access [ARA]). PPP also has built-in security mechanisms (such as Challenge Handshake Authentication Protocol [CHAP] and Password Authentication Protocol [PAP]). PPP relies on two protocols: Link Control Protocol (LCP) and Network Control Protocol (NCP).
RIP—Routing Information Protocol. A version of Interior Gateway Protocol (IGP) that is supplied with UNIX Berkeley Standard Distribution (BSD) systems. Routing Information Protocol (RIP) is the most common IGP in the Internet. It uses hop count as a routing metric.
RSP—Route Switch Processor. A processor module used in the Cisco 7500 series routers that integrates the functions of the Route Processor and the Switch Processor. The former contains the CPU, system software, and most of the router's memory components; the latter is a processor module that acts as the administrator for all Cisco Extended Bus activities.
VIP—Versatile Interface Processor. An interface card that is used in Cisco 7000 and Cisco 7500 series routers. It can hold different port adapters for interfaces to various media (Ethernet, Token Ring, FDDI, ATM, and so on). The VIP supports two port adapters, standard packet delivery, distributed Cisco Express Forwarding, and feature off-load.
Virtual Bundle Interface—An interface that represents the master link of a bundle. It is not tied to any physical interface. Data going over the bundle is transmitted and received through the master link.
WFQ—weighted fair queueing. A congestion management algorithm that identifies conversations (in the form of traffic streams), separates packets that belong to each conversation, and ensures that capacity is shared fairly among the individual conversations. WFQ is an automatic way of stabilizing network behavior during congestion and results in improved performance and reduced retransmission.
WRED—weighted random early detection. A queueing method that ensures that high-precedence traffic has lower loss rates than other traffic during times of congestion.