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diff --git a/doc/user/pathd.rst b/doc/user/pathd.rst new file mode 100644 index 0000000..f0b76f1 --- /dev/null +++ b/doc/user/pathd.rst @@ -0,0 +1,616 @@ +.. _path: + +**** +PATH +**** + +:abbr:`PATH` is a daemon that handles the installation and deletion +of Segment Routing (SR) Policies. +Based on MPLS (This means that your OS of choice must support MPLS), +SR add a stack of MPLS labels to ingress packets so these +packets are egress through the desired path. + +.. image:: images/pathd_general.png + +The SR policies and Segment Lists can be configured either locally by means +of vtysh or centralized based on a SDN controller (ODL, Cisco, ...) +communicating using the PCEP protocol (:rfc:`5440`). + + +.. _starting-path: + +Configuration +============= + +Explicit Segment Lists +---------------------- + +This is the simplest way of configuration, no remote PCE is necessary. +In order to create a config that match the graphics used in this documentation, +we will create a segment list (SL) called SL1 with an element for each hop and +that element will be assigned a MPLS label. +Then the SL1 will be used in the policy ``example1``, please note also the +preference as in the case of multiple segment list it will be used with the +criteria of bigger number more preference. +Let see now the final configuration that match the graphics shown above. + + +.. code-block:: frr + + segment-routing + traffic-eng + segment-list SL1 + index 10 mpls label 16001 + index 20 mpls label 16002 + ! + policy color 1 endpoint 192.0.2.4 + name example1 + binding-sid 1111 + candidate-path preference 100 name CP1 explicit segment-list SL1 + + +Explicit Segment Lists and Traffic Engineering Database (TED) +------------------------------------------------------------- + +Sometimes is difficult to know the values of MPLS labels +(adjacency changes,...). +Based on the support of IS-IS or OSPF we can activate TED support what will +allow pathd to resolve MPLS based in different types of segments +(:rfc: `draft-ietf-spring-segment-routing-policy-07`). The supported types are +Type C (prefix and local interface), Type E (prefix and algorithm), +Type F (a pair of IP's). +So the configuration would change to this + +.. code-block:: frr + + segment-routing + traffic-eng + mpls-te on + mpls-te import ospfv2 + segment-list SL1 + index 10 nai prefix 10.1.2.1/32 iface 1 + index 20 nai adjacency 10.1.20.1 10.1.20.2 + ! + policy color 1 endpoint 192.0.2.4 + name example1 + binding-sid 1111 + candidate-path preference 100 name CP1 explicit segment-list SL1 + + +In this case no MPLS are provided but the pathd TED support will resolve the +configuration provided to corresponding MPLS labels. + +.. note:: + Please note the ``mpls-te`` configuration added that activate the TED + support and points to ``ospfv2`` so + the ospfv2 (:ref:`ospf-traffic-engineering`) daemon must be also + running and configure to export TED information. + +.. note:: + It would be the same for isis (:ref:`isis-traffic-engineering`) but in the + moment of writting it's not fully tested. + +Dynamic Segment Lists +--------------------- + +One of the useful options to configure is the creation of policies with +the dynamic option. In this case based on a given endpoint the SL will be +,first calculated, and then sended by means of PCEP protocol by the configured +PCE. + +.. code-block:: frr + + traffic-eng + ! + pcep + ! + pce PCE1 + address ip 192.0.2.10 + ! + pcc + peer PCE1 precedence 10 + ! + policy color 1 endpoint 192.0.2.4 + name example + binding-sid 1111 + candidate-path preference 100 name CP2 dynamic + +.. note:: + Please note the configuration for the remote pce which allows pathd to + connect to the given PCE and act as a PCC (PCEP Client) + +.. note:: + If the TED support feature is active, the data obtained from PCE will + be validated, so in a SL from PCEP/PCE the IP and MPLS will be checked + against local TED obtained and built from the igp configured in that + case. + +.. image:: images/pathd_config.png + +Pce Initiated +------------- + +We can step forward in the use of our controller not only by asking to +calculate paths to an endpoint but also to create the whole policies in the +controller and obtain those by means of the PCEP protocol. + + +.. code-block:: frr + + traffic-eng + ! + pcep + ! + pce PCE1 + address ip 192.0.2.10 + pce-initiated + ! + pce PCE2 + address ip 192.0.2.9 + pce-initiated + ! + pcc + peer PCE1 precedence 10 + peer PCE2 precedence 20 + ! + +.. note:: + Now there is no locally created policies in the config as they will + be obtain from the configured pce. + Please check command :clicmd:`show sr-te policy` in ``vtysh`` to see + the obtained policies. + +.. note:: + Another interesting command is :clicmd:`show mpls table` + to check the installed mpls configuration based in those obtained + policies. + +.. note:: + SR Policies could be a mix of local, remote obtained from PCE and + delegated to a PCE (but while testing Pce Initiated with Cisco PCE, + happens that controller sends PCE initiated delete commands to delete + the locally created configuration related to that PCE). + + +.. image:: images/pathd_initiated_multi.png + +Starting +============= + +Default configuration file for *pathd* is :file:`pathd.conf`. The typical +location of :file:`pathd.conf` is |INSTALL_PREFIX_ETC|/pathd.conf. + +If the user is using integrated config, then :file:`pathd.conf` need not be +present and the :file:`frr.conf` is read instead. + +.. program:: pathd + +:abbr:`PATH` supports all the common FRR daemon start options which are +documented elsewhere. + +PCEP Support +============ + +A pceplib is included in the frr source tree and build by default. + + +To start pathd with pcep support the extra parameter `-M pathd_pcep` should be +passed to the pathd daemon. + +An example of command line with pcep module could be this + +.. code-block:: frr + + pathd -u root -g root -f pathd.conf -z /tmp/zebra-demo1.sock --vty_socket=/var/run/demo1.vty -i /tmp/pathd-demo1.pid -M frr/modules/pathd_pcep.so --log file:/tmp/kk.txt + +Pathd Configuration +=================== + +Example: + +.. code-block:: frr + + debug pathd pcep basic + segment-routing + traffic-eng + mpls-te on + mpls-te import ospfv2 + segment-list SL1 + index 10 mpls label 16010 + index 20 mpls label 16030 + ! + segment-list SL2 + index 10 nai prefix 10.1.2.1/32 iface 1 + index 20 nai adjacency 10.1.20.1 10.1.20.2 + index 30 nai prefix 10.10.10.5/32 algorithm 0 + index 40 mpls label 18001 + ! + policy color 1 endpoint 192.0.2.1 + 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 192.0.2.1 + tcp-md5-auth secret + timer keep-alive 30 + ! + pce PCE1 + config GROUP1 + address ip 192.0.2.10 + ! + pce PCE2 + config GROUP1 + address ip 192.0.2.9 + ! + pcc + peer PCE1 precedence 10 + peer PCE2 precedence 20 + ! + ! + ! + ! + + +.. _path-commands: + +Configuration Commands +---------------------- + +.. clicmd:: segment-routing + + Configure segment routing. + +.. clicmd:: traffic-eng + + Configure segment routing traffic engineering. + +.. clicmd:: mpls-te <on|off> + + Activate/Deactivate use of internal Traffic Engineering Database + +.. clicmd:: mpls-te import <ospfv2|ospfv3|isis> + + Load data from the selected igp + +.. clicmd:: segment-list NAME + + Delete or start a segment list definition. + +.. clicmd:: index INDEX mpls label LABEL +.. clicmd:: index INDEX nai adjacency A.B.C.D A.B.C.D +.. clicmd:: index INDEX nai prefix A.B.C.D/M algorithm <0|1> +.. clicmd:: index INDEX nai prefix A.B.C.D/M iface (0-65535) + + Delete or specify a segment in a segment list definition. + + +.. clicmd:: policy color COLOR endpoint ENDPOINT + + Delete or start a policy definition. + + +.. clicmd:: name NAME + + Specify the policy name. + + +.. clicmd:: binding-sid LABEL + + Specify the policy SID. + + +.. clicmd:: candidate-path preference PREFERENCE name NAME explicit segment-list SEGMENT-LIST-NAME + + Delete or define an explicit candidate path. + + +.. clicmd:: candidate-path preference PREFERENCE name NAME dynamic + + Delete or start a dynamic candidate path definition. + + +.. clicmd:: affinity <exclude-any|include-any|include-all> BITPATTERN + + Delete or specify an affinity constraint for a dynamic candidate path. + + +.. clicmd:: bandwidth BANDWIDTH [required] + + Delete or specify a bandwidth constraint for a dynamic candidate path. + + +.. clicmd:: 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 + + +.. clicmd:: 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] + + +.. clicmd:: 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 + + +.. clicmd:: pcep + + Configure PCEP support. + + +.. clicmd:: pce-config NAME + + Define a shared PCE configuration that can be used in multiple PCE + declarations. + + +.. clicmd:: pce NAME + + Define or delete a PCE definition. + + +.. clicmd:: config WORD + + Select a shared configuration. If not defined, the default + configuration will be used. + + +.. clicmd:: 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. + + +.. clicmd:: 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. + + This can be specified in either the PCC peer definition or in a + configuration group. + + +.. clicmd:: tcp-md5-auth WORD + + Enable TCP MD5 security with the given secret. + + This can be specified in either the PCC peer definition or in a + configuration group. + + +.. clicmd:: sr-draft07 + + Specify if a PCE only support segment routing draft 7, this flag will limit + the PCC behavior to this draft. + + This can be specified in either the PCC peer definition or in a + configuration group. + + +.. clicmd:: pce-initiated + + Specify if PCE-initiated LSP should be allowed for this PCE. + + This can be specified in either the PCC peer definition or in a + configuration group. + + +.. clicmd:: timer [keep-alive (1-63)] [min-peer-keep-alive (1-255)] [max-peer-keep-alive (1-255)] [dead-timer (4-255)] [min-peer-dead-timer (4-255)] [max-peer-dead-timer (4-255)] [pcep-request (1-120)] [session-timeout-interval (1-120)] [delegation-timeout (1-60)] + + Specify the PCEP timers. + + This can be specified in either the PCC peer definition or in a + configuration group. + + +.. clicmd:: pcc + + Disable or start the definition of a PCC. + + +.. clicmd:: msd (1-32) + + Specify the maximum SID depth in a PCC definition. + + +.. clicmd:: peer WORD [precedence (1-255)] + + Specify a peer and its precedence in a PCC definition. + + +Introspection Commands +---------------------- + +.. clicmd:: show sr-te policy [detail] + + Display the segment routing policies. + +.. code-block:: frr + + router# show sr-te policy + + Endpoint Color Name BSID Status + ------------------------------------------ + 192.0.2.1 1 default 4000 Active + + +.. code-block:: frr + + router# show sr-te policy detail + + Endpoint: 192.0.2.1 Color: 1 Name: LOW_DELAY BSID: 4000 Status: Active + Preference: 100 Name: cand1 Type: explicit Segment-List: sl1 Protocol-Origin: Local + * Preference: 200 Name: cand1 Type: dynamic Segment-List: 32453452 Protocol-Origin: PCEP + +The asterisk (*) marks the best, e.g. active, candidate path. Note that for segment-lists which are +retrieved via PCEP a random number based name is generated. + + +.. clicmd:: show sr-te pcep counters + + Display the counters from pceplib. + + +.. clicmd:: show sr-te pcep pce-config [NAME] + + Display a shared configuration. if no name is specified, the default + configuration will be displayed. + + +.. clicmd:: show sr-te pcep pcc + + Display PCC information. + + +.. clicmd:: show sr-te pcep session [NAME] + + Display the information of a PCEP session, if not name is specified all the + sessions will be displayed. + + +Utility Commands +---------------- + +.. clicmd:: clear sr-te pcep session [NAME] + + Reset the pcep session by disconnecting from the PCE and performing the + normal reconnection process. No configuration is changed. + + +Usage with BGP route-maps +========================= + +It is possible to steer traffic 'into' a segment routing policy for routes +learned through BGP using route-maps: + +.. code-block:: frr + + route-map SET_SR_POLICY permit 10 + set sr-te color 1 + ! + router bgp 1 + bgp router-id 192.0.2.2 + neighbor 192.0.2.1 remote-as 1 + neighbor 192.0.2.1 update-source lo + ! + address-family ipv4 unicast + neighbor 192.0.2.1 next-hop-self + neighbor 192.0.2.1 route-map SET_SR_POLICY in + redistribute static + exit-address-family + ! + ! + +In this case, the SR Policy with color `1` and endpoint `192.0.2.1` is selected. + + +Sample configuration +==================== + +.. code-block:: frr + + ! Default pathd configuration sample + ! + password frr + log stdout + + segment-routing + traffic-eng + segment-list test1 + index 10 mpls label 123 + index 20 mpls label 456 + ! + segment-list test2 + index 10 mpls label 321 + index 20 mpls label 654 + ! + policy color 1 endpoint 192.0.2.1 + name one + binding-sid 100 + candidate-path preference 100 name test1 explicit segment-list test1 + candidate-path preference 200 name test2 explicit segment-list test2 + ! + policy color 2 endpoint 192.0.2.2 + name two + binding-sid 101 + candidate-path preference 100 name def explicit segment-list test2 + candidate-path preference 200 name dyn dynamic + bandwidth 12345 + metric bound abc 16 required + metric te 10 + ! + ! + pcep + pcc-peer PCE1 + address ip 127.0.0.1 + sr-draft07 + ! + pcc + peer PCE1 + ! + ! + ! + |