Label Range and TTL
From the /mpls menu it is possible to assign specific dynamic label range and TTL propagation. If for some reason static label mapping is used then the dynamic range can be adjusted to exclude statically assigned label numbers from being dynamically assigned by any of the label distribution protocols.
| Property | Description |
|---|---|
| dynamic-label-range (range of integer[16..1048575]; Default: 16-1048575) | Range of Label numbers used for dynamic allocation. The first 16 labels are reserved for special purposes (as defined in RFC). If you intend to configure labels statically then adjust the dynamic default range not to include numbers that will be used in a 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 the MPLS cloud will be invisible from traceroutes. |
MPLS MTU
Configuration of MPLS MTU (path MTU + MPLS tag size) is useful in cases when there is a large variety of possible MTUs along the path. Configuring MPLS MTU to a minimum value that can pass all the hops will ensure that the MPLS packet will not be silently dropped on the devices that do not support big enough MTU.
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| Code Block | ||
|---|---|---|
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[admin@rack1_b35_CCR1036] /mpls/interface> print
Flags: X - disabled; * - builtin
0 ;;; router-test
interface=ether1 mpls-mtu=1580 input=yes
1 ;;; router-test
interface=ether2 mpls-mtu=1580 input=yes
2 interface=all mpls-mtu=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 (name; Default:) | Name of the interface or interface-list to match. |
| input (yes | no; Default: yes) | Whether to allow MPLS input on the interface |
| mpls-mtu (integer [512..65535]; Default: 1508) | The option represents how big packets can be carried over the interface with added MPLS labels. |
| Note |
|---|
Listed entries are ordered, and the first entry (iterating from the top to the bottom) that matches the interface will be used. |
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Read more on MTUs in the MTU in RouterOS article.
Forwarding Table
Sub-menu: /mpls forwarding-table
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