Manual:MPLS

Sub Categories

List of reference sub-pages	Case studies	List of examples
Interface vpls traffic-eng MPLS ldp traffic-eng	General MPLS Overview and RouterOS MPLS Implementation Status EXP bit behaviour L2MTU Layer2 VPN LDP and LDP based VPLS BGP based VPLS Cisco style VPLS VPLS Control Word Layer3 VPN Virtual Routing and Forwarding (VRF) OSPF as PE-CE routing protocol EBGP as PE-CE routing protocol Traffic Engineering TE Tunnels TE Tunnel Bandwidth Control	General MPLS over PPPoE Layer2 VPN Layer3 VPN A complete Layer-3 MPLS VPN example VRF Route Leaking Internet access from VRF Internet access from VRF with NAT Traffic Engineering Simple TE configuration TE tunnels for VPLS

Summary

MikroTik RouterOS supports MPLS. All MikroTik RouterBOARD hardware products support MPLS.

General Porperties

Property	Description
dynamic-label-range (range of integer[16..1048575]; Default: 16-1048575)	Range of Label numbers used for dynamic allocation. First 16 labels are reserved for special purposes (as defined in RFC). If you intend to configure labels statically then adjust dynamic default range not to include numbers that will be used in static configuration.
propagate-ttl (yes | no; Default: yes)	Whether to copy TTL values from IP header to MPLS header. If this option is set to no then hops inside MPLS cloud will be invisible from traceroutes.

Forwarding Table

Sub-menu: /mpls forwarding-table

Entries in this sub-menu shows label bindings for specific routes that will be used in MPLS label switching. Properties in this menu are read-only

Property	Description
bytes (integer)	Total number of packet bytes matched by this entry
destination (IP/Mask)	Destination prefix for which labels are assigned
in-label (integer)	Label number for incoming packet
interface (string)
ldp (yes | no)	Whether labels are LDP signaled
nexthop (IP)	IP address of the nexthop
out-label (integer)	Label number which is added or switched to for outgoing packet.
packets (integer)	Number of packets matched by this entry
traffic-eng (yes | no)	Shows whether entry is signaled by RSVP-TE (Traffic Engineering)
vpls (yes | no)	Shows whether entry is used for VPLS tunnels.

For example we have forwarding table as shown below.

[admin@RB493G] /mpls forwarding-table> print 
Flags: L - ldp, V - vpls, T - traffic-eng 
 #   IN-LABEL      OUT-LABELS   DESTINATION                    IN NEXTHOP        
 0   expl-null    
 1 L 105                        10.255.255.36/32               lo 10.5.101.36    
 2 L 120           112          3.3.3.1/32                     lo 10.5.101.3     
 3 L 121           113          3.3.3.2/32                     lo 10.5.101.3     
[admin@RB493G] /mpls forwarding-table> 

You can see that all labels are LDP signaled. Note that for entry #1 there is no out-label, it means that MPLS label switching will not occur, packet will be sent out as regular IP packet. In the other hand entry #2 has in-label and out-label, which means that during packet forwarding label will be switched from 120 to 112.

Interface

Sub-menu: /mpls interface

This menu allows to configure MTUs including MPLS headers that interface can forward without fragmentation.

Note: If Ethernet card does not support Jumbo frames, then MPLS MTU for all interfaces on all devices participating in LSP should be set to 1500

Properties

Property	Description
comment (string; Default: )	Short description of the interface
disabled (yes | no; Default: no)	If set to yes then this configuration is ignored.
interface (string | all; Default: all)	Interface name to which apply settings. If set to all then the same config will be used for every interface if there is no specific configuration for the interface.
mpls-mtu (integer [512..65535]; Default: 1508)	Option represents how big packets can be carried over the interface with added MPLS labels. Read More >>

In RouterOS by default have entry which sets MS MTU to 1508 for all interfaces.

[admin@RB493G] /mpls interface> print 
Flags: X - disabled 
 #   INTERFACE                                                           MPLS-MTU
 0   all                                                                     1508

Local Bindings

Sub-menu: /mpls local-bindings

This sub-menu shows labels bound to the routes locally in the router

Remote Bindings

Sub-menu: /mpls remote-bindings

Sub-menu shows label bindings for routes received from other routers. This table is used to build Forwarding Table

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