PATH¶

PATH is a daemon that handles the installation and deletion of Segment Routing (SR) Policies.

Starting PATH¶

Default configuration file for pathd is pathd.conf. The typical location of pathd.conf is /etc/frr/pathd.conf.

If the user is using integrated config, then pathd.conf need not be present and the frr.conf is read instead.

PATH supports all the common FRR daemon start options which are documented elsewhere.

PCEP Support¶

To build the PCC for pathd, the externall library pceplib 1.2 is required.

To build FRR with support for PCEP the following steps must be followed:

Checkout and build pceplib:

` $ git clone https://github.com/volta-networks/pceplib $ cd pceplib $ make $ make install $ export PCEPLIB_ROOT=$PWD `

Configure FRR with the extra parameters:

` --enable-pcep LDFLAGS="-L${PCEPLIB_ROOT}/install/lib" CPPFLAGS="-I${PCEPLIB_ROOT}/install/include" `

To start pathd with pcep support the extra parameter -M pathd_pcep should be passed to the pathd daemon.

Pathd Configuration¶

Example:

debug pathd pcep basic
segment-routing
 traffic-eng
  segment-list SL1
   index 10 mpls label 16010
   index 20 mpls label 16030
  !
  policy color 1 endpoint 1.1.1.1
   name default
   binding-sid 4000
   candidate-path preference 100 name CP1 explicit segment-list SL1
   candidate-path preference 200 name CP2 dynamic
    affinity include-any 0x000000FF
    bandwidth 100000
    metric bound msd 16 required
    metric te 10
    objective-function mcp required
  !
  pcep
   pce-config GROUP1
    source-address 1.1.1.1
    tcp-md5-auth secret
    timer keep-alive 30
   !
   pce PCE1
    config GROUP1
    address ip 10.10.10.10
   !
   pce PCE2
    config GROUP1
    address ip 9.9.9.9
   !
   pcc
    peer PCE1 precedence 10
    peer PCE2 precedence 20
   !
  !
 !
!

Configuration Commands¶

segment-routing¶: Configure segment routing.

traffic-eng¶: Configure segment routing traffic engineering.

[no] segment-list NAME¶: Delete or start a segment list definition.

[no] index INDEX mpls label LABEL [nai node ADDRESS]¶: Delete or specify a segment in a segment list definition.

[no] policy color COLOR endpoint ENDPOINT¶: Delete or start a policy definition.

name NAME¶: Specify the policy name.

binding-sid LABEL¶: Specify the policy SID.

[no] candidate-path preference PREFERENCE name NAME explicit segment-list SEGMENT-LIST-NAME¶: Delete or define an explicit candidate path.

[no] candidate-path preference PREFERENCE name NAME dynamic¶: Delete or start a dynamic candidate path definition.

[no] affinity {exclude-any|include-any|include-all} BITPATTERN¶: Delete or specify an affinity constraint for a dynamic candidate path.

[no] bandwidth BANDWIDTH [required]¶: Delete or specify a bandwidth constraint for a dynamic candidate path.

[no] metric [bound] METRIC VALUE [required]¶

Delete or specify a metric constraint for a dynamic candidate path.

The possible metrics are:

igp: IGP metric
te: TE metric
hc: Hop Counts
abc: Aggregate bandwidth consumption
mll: Load of the most loaded link
igp: Cumulative IGP cost
cte: Cumulative TE cost
igp: P2MP IGP metric
pte: P2MP TE metric
phc: P2MP hop count metric
msd: Segment-ID (SID) Depth
pd: Path Delay metric
pdv: Path Delay Variation metric
pl: Path Loss metric
ppd: P2MP Path Delay metric
pdv: P2MP Path Delay variation metric
ppl: P2MP Path Loss metric
nap: Number of adaptations on a path
nlp: Number of layers on a path
dc: Domain Count metric
bnc: Border Node Count metric

[no] objective-function OBJFUN1 [required]¶

Delete or specify a PCEP objective function constraint for a dynamic candidate path.

The possible functions are:

mcp: Minimum Cost Path [RFC5541]
mlp: Minimum Load Path [RFC5541]
mbp: Maximum residual Bandwidth Path [RFC5541]
mbc: Minimize aggregate Bandwidth Consumption [RFC5541]
mll: Minimize the Load of the most loaded Link [RFC5541]
mcc: Minimize the Cumulative Cost of a set of paths [RFC5541]
spt: Shortest Path Tree [RFC8306]
mct: Minimum Cost Tree [RFC8306]
mplp: Minimum Packet Loss Path [RFC8233]
mup: Maximum Under-Utilized Path [RFC8233]
mrup: Maximum Reserved Under-Utilized Path [RFC8233]
mtd: Minimize the number of Transit Domains [RFC8685]
mbn: Minimize the number of Border Nodes [RFC8685]
mctd: Minimize the number of Common Transit Domains [RFC8685]
msl: Minimize the number of Shared Links [RFC8800]
mss: Minimize the number of Shared SRLGs [RFC8800]
msn: Minimize the number of Shared Nodes [RFC8800]

[no] debug pathd pcep [basic|path|message|pceplib]¶

Enable or disable debugging for the pcep module:

basic: Enable basic PCEP logging

path: Log the path structures

message: Log the PCEP messages

pceplib: Enable pceplib logging

pcep¶: Configure PCEP support.

[no] pce-config NAME¶: Define a shared PCE configuration that can be used in multiple PCE declarations.

[no] pce NAME¶: Define or delete a PCE definition.

config WORD¶: Select a shared configuration. If not defined, the default configuration will be used.

address <ip A.B.C.D | ipv6 X:X::X:X> [port (1024-65535)]¶

Define the address and port of the PCE.

If not specified, the port is the standard PCEP port 4189.

This should be specified in the PCC peer definition.

source-address [ip A.B.C.D | ipv6 X:X::X:X] [port PORT]¶

Define the address and/or port of the PCC as seen by the PCE. This can be used in a configuration group or a PCC peer declaration.

If not specified, the source address will be the router identifier selected by zebra, and the port will be the standard PCEP port 4189.