API Model

API Model

Problem Description

Currently Neutron does not support service function chaining. To support service function chaining, Service VMs must be attached at points in the network and then traffic must be steered between these attachment points. Please refer to Neutron Service Chain blue-print and Bugs [1] [2] related to this specification for more information.

Proposed Change

All Neutron network services and VMs are connected to a Neutron network via Neutron ports. This makes it possible to create a traffic steering model for service chaining that uses only Neutron ports. This traffic steering model has no notion of the actual services attached to these Neutron ports.

The service VM hosting the service functions is instantiated and configured, then VNICs are added to the VM and then these VNICs are attached to the network by Neutron ports. Once the service function is attached to Neutron ports, the ports may be included in a “port chain” to allow the service function to provide treatment to the user’s traffic.

A Port Chain (Service Function Path) consists of:

  • a set of Neutron ports, to define the sequence of service functions
  • a set of flow classifiers, to specify the classified traffic flows to enter the chain

If a service function has a pair of ports, the first port in the port-pair is the ingress port of the service function, and the second port is the egress port of the service function. If a service function has one bidirectional port, then both ports in the port-pair have the same value. A Port Chain is a directional service chain. The first port of the first port-pair is the head of the service chain. The second port of the last port-pair is the tail of the service chain. A bidirectional service chain would be composed of two unidirectional Port Chains.

For example, [{‘p1’: ‘p2’}, {‘p3’: ‘p4’}, {‘p5’: ‘p6’}] represents:

   +------+     +------+     +------+
   | SF1  |     | SF2  |     | SF3  |
   +------+     +------+     +------+
   p1|  |p2     p3|  |p4      p5| |p6
     |  |         |  |          | |
->---+  +---------+  +----------+ +---->

where p1 is the head of the Port Chain and p6 is the tail of the Port Chain, and SF1 has ports p1 and p2, SF2 has ports p3 and p4, and SF3 has ports p5 and p6.

In order to create a chain, the user needs to have the actual port objects. The work flow would typically be:

  1. create the ports
  2. create the chain
  3. boot the vm’s passing the ports as nic’s parameters

The sequence of 2. and 3. can be switched.

A SF’s Neutron port may be associated with more than one Port Chain to allow a service function to be shared by multiple chains.

If there is more than one service function instance of a specific type available to meet the user’s service requirement, their Neutron ports are included in the port chain as a sub-list. For example, if {p3, p4}, {p7, p8} are the port-pairs of two FW instances, they both may be included in a port chain for load distribution as shown below:

[{'p1': 'p2'}, [{'p3': 'p4'},{'p7': 'p8'}], {'p5': 'p6'}]

Flow classifiers are used to select the traffic that can access the chain. Traffic that matches any flow classifier will be directed to the first port in the chain. The flow classifier will be a generic independent module and may be used by other projects like FW, QOS, etc.

A flow classifier cannot be part of two different port-chains otherwise ambiguity will arise as to which chain path that flow’s packets should go. A check will be made to ensure no ambiguity. But multiple flow classifiers can be associated with a port chain since multiple different types of flows can request the same service treatment path.

CLI Commands

Syntax:

openstack sfc port pair create [-h]
        [--description <description>]
        --ingress <port-id>
        --egress <port-id>
        [--service-function-parameters <parameter>] PORT-PAIR-NAME

openstack sfc port pair group create [-h]
        [--description <description>]
        --port-pair <port-pair-id>
        [--port-pair-group-parameters <parameter>] PORT-PAIR-GROUP-NAME

openstack sfc flow classifier create [-h]
        [--description <description>]
        [--protocol <protocol>]
        [--ethertype <Ethertype>]
        [--source-port <Minimum source protocol port>:<Maximum source protocol port>]
        [--destination-port <Minimum destination protocol port>:<Maximum destination protocol port>]
        [--source-ip-prefix <Source IP prefix>]
        [--destination-ip-prefix <Destination IP prefix>]
        [--logical-source-port <Neutron source port>]
        [--logical-destination-port <Neutron destination port>]
        [--l7-parameters <L7 parameter>] FLOW-CLASSIFIER-NAME

openstack sfc port chain create [-h]
        [--description <description>]
         --port-pair-group <port-pair-group-id>
        [--flow-classifier <classifier-id>]
        [--chain-parameters <chain-parameter>] PORT-CHAIN-NAME

openstack sfc port chain create

The sfc port chain create command returns the ID of the Port Chain.

Each --port-pair-group option specifies a type of SF. If a chain consists of a sequence of different types of SFs, then the chain will have multiple “port-pair-group”s. There must be at least one “port-pair-group” in the Port Chain.

The -flow-classifier option may be repeated to associate multiple flow classifiers with a port chain, with each classifier identifying a flow. If the flow-classifier is not specified, then no traffic will be steered through the chain.

One chain parameter option is currently defined. More parameter options can be added in future extensions to accommodate new requirements. The correlation parameter is used to specify the type of chain correlation mechanism. This parameter allows different correlation mechanisms to be selected. The chain correlation concept is equivalent to SFC Encapsulation, as defined in RFC 7665. The default is “mpls”, but “nsh” is also supported.

The sfc port chain create command returns the ID of a Port chain.

A port chain can be created, read, updated and deleted, and when a chain is created/read/updated/deleted, the options that are involved would be based on the CRUD in the “Port Chain” resource table below.

openstack sfc port pair group create

Inside each “port-pair-group”, there could be one or more port-pairs. Multiple port-pairs may be included in a “port-pair-group” to allow the specification of a set of functionally equivalent SFs that can be be used for load distribution, i.e., the --port-pair option may be repeated for multiple port-pairs of functionally equivalent SFs.

The sfc port pair group create command returns the ID of a Port Pair group.

openstack sfc port pair create

A Port Pair represents a service function instance. The ingress port and the egress port of the service function may be specified. If a service function has one bidirectional port, the ingress port has the same value as the egress port. The --service-function-parameters option allows the passing of SF specific parameter information to the data path. These include:

  • The correlation parameter is used to specify the type of chain correlation mechanism supported by a specific SF. This is needed by the data plane switch to determine how to associate a packet with a chain. This will be set to “none” for now since there is no correlation mechanism supported by the SF. In the future, it can be extended to include “mpls”, “nsh”, etc.. If this parameter is not specified, it will default to “none”.
  • The weight parameter is used to specify the weight for each SF for load distribution in a port pair group. This represents a percentage of the traffic to be sent to each SF.

The sfc port pair create command returns the ID of a Port Pair.

openstack sfc flow classifier create

A combination of the “source” options defines the source of the flow. A combination of the “destination” options defines the destination of the flow. The l7_parameter is a place-holder that may be used to support flow classification using L7 fields, such as URL. If an option is not specified, it will default to wildcard value except for ethertype which defaults to ‘IPv4’, for logical-source-port and logical-destination-port which defaults to none.

The sfc flow classifier create command returns the ID of a flow classifier.

Data Model Impact

Data model:

 +-------+        +----------+        +------------+
 | Port  |--------| Port Pair|--------| Port Pairs |
 | Chain |*      *| Groups   | 1     *|            |
 +-------+        +----------+        +------------+
   |1
   |
   |*
+--------------+
| Flow         |
| Classifiers  |
+--------------+

New objects:

Port Chain
  • id - Port chain ID.
  • project_id - Tenant ID.
  • name - Readable name.
  • description - Readable description.
  • port_pair_groups - List of port-pair-group IDs.
  • flow_classifiers - List of flow-classifier IDs.
  • chain_parameters - Dict. of chain parameters.
  • chain_id - Data-plane chain path ID.
Port Pair Group
  • id - Port pair group ID.
  • project_id - Tenant ID.
  • name - Readable name.
  • description - Readable description.
  • port_pairs - List of service function (Neutron) port-pairs.
  • port_pair_group_parameters - Dict. of port pair group parameters.
Port Pair
  • id - Port pair ID.
  • project_id - Tenant ID.
  • name - Readable name.
  • description - Readable description.
  • ingress - Ingress port.
  • egress - Egress port.
  • service_function_parameters - Dict. of service function parameters
Flow Classifier
  • id - Flow classifier ID.
  • project_id - Tenant ID.
  • name - Readable name.
  • description - Readable description.
  • ethertype - Ethertype (‘IPv4’/’IPv6’).
  • protocol - IP protocol.
  • source_port_range_min - Minimum source protocol port.
  • source_port_range_max - Maximum source protocol port.
  • destination_port_range_min - Minimum destination protocol port.
  • destination_port_range_max - Maximum destination protocol port.
  • source_ip_prefix - Source IP address or prefix.
  • destination_ip_prefix - Destination IP address or prefix.
  • logical_source_port - Neutron source port.
  • logical_destination_port - Neutron destination port.
  • l7_parameters - Dictionary of L7 parameters.

REST API

Port Chain Operations:

Operation URL Description
POST /sfc/port_chains Create a Port Chain
PUT /sfc/port_chains/{chain_id} Update a specific Port Chain
DELETE /sfc/port_chains/{chain_id} Delete a specific Port Chain
GET /sfc/port_chains List all Port Chains for specified tenant
GET /sfc/port_chains/{chain_id} Show information for a specific Port Chain

Port Pair Group Operations:

Operation URL Description
POST /sfc/port_pair_groups Create a Port Pair Group
PUT /sfc/port_pair_groups/{group_id} Update a specific Port Pair Group
DELETE /sfc/port_pair_groups/{group_id} Delete a specific Port Pair Group
GET /sfc/port_pair_groups List all Port Pair Groups for specified tenant
GET /sfc/port_pair_groups/{group_id} Show information for a specific Port Pair

Port Pair Operations:

Operation URL Description
POST /sfc/port_pairs Create a Port Pair
PUT /sfc/port_pairs/{pair_id} Update a specific Port Pair
DELETE /sfc/port_pairs/{pair_id} Delete a specific Port Pair
GET /sfc/port_pairs List all Port Pairs for specified tenant
GET /sfc/port_pairs/{pair_id} Show information for a specific Port Pair

Flow Classifier Operations:

Operation URL Description
POST /sfc/flow_classifiers Create a Flow-classifier
PUT /sfc/flow_classifiers/{flow_id} Update a specific Flow-classifier
DELETE /sfc/flow_classifiers/{flow_id} Delete a specific Flow-classifier
GET /sfc/flow_classifiers List all Flow-classifiers for specified tenant
GET /sfc/flow_classifiers/{flow_id} Show information for a specific Flow-classifier

REST API Impact

The following new resources will be created as a result of the API handling.

Port Chain resource:

Attribute Name Type Access Default Value CRUD Description
id uuid RO, all generated R Port Chain ID.
project_id uuid RO, all from auth token CR Tenant ID.
name string RW, all ‘’ CRU Port Chain name.
description string RW, all ‘’ CRU Port Chain description.
port_pair_groups list(uuid) RW, all N/A CRU List of port-pair-groups.
flow_classifiers list(uuid) RW, all [] CRU List of flow-classifiers.
chain_parameters dict RW, all mpls CR Dict. of parameters: ‘correlation’:String
chain_id integer RW, all Any CR Data-plane Chain Path ID.

The data-plane chain path ID is normally generated by the data-plane implementation. However, an application may optionally generate its own data-plane chain path ID and apply it to the Port Chain using the chain_id attribute.

Port Pair Group resource:

Attribute Name Type Access Default Value CRUD Description
id uuid RO, all generated R Port pair group ID.
project_id uuid RO, all from auth token CR Tenant ID.
name string RW, all ‘’ CRU Port pair group name.
description string RW, all ‘’ CRU Port pair group description.
port_pairs list RW, all N/A CRU List of port-pairs.
port_pair_group _parameters dict RW, all ‘’ CR Dict. of parameters: ‘lb_fields’:String ‘service_type’:String

Port Pair resource:

Attribute Name Type Access Default CRUD Description
id uuid RO, all generated R Port pair ID.
project_id uuid RO, all from auth token CR Tenant ID.
name string RW, all ‘’ CRU Port pair name.
description string RW, all ‘’ CRU Port pair description.
ingress uuid RW, all N/A CR Ingress port ID.
egress uuid RW, all N/A CR Egress port ID.
service_function_parameters dict RW, all None CR Dict. of parameters: ‘correlation’:String ‘weight’:Integer

Flow Classifier resource:

Attribute Name Type Access Default Value CRUD Description
id uuid RO, all generated R Flow-classifier ID.
project_id uuid RO, all from auth token CR Tenant ID.
name string RW, all ‘’ CRU Flow-classifier name.
description string RW, all ‘’ CRU Flow-classifier description.
ethertype string RW, all ‘IPv4’ CR L2 ethertype. Can be ‘IPv4’ or ‘IPv6’ only.
protocol string RW, all Any CR IP protocol name.
source_port_range_min integer RW, all Any CR Minimum source protocol port.
source_port_range_max integer RW, all Any CR Maximum source protocol port.
destination_port_range_min integer RW, all Any CR Minimum destination protocol port.
destination_port_range_max integer RW, all Any CR Maximum destination protocol port.
source_ip_prefix CIDR RW, all Any CR Source IPv4 or IPv6 prefix.
destination_ip_prefix CIDR RW, all Any CR Destination IPv4 or IPv6 prefix.
logical_source_port uuid RW, all None CR Neutron source port.
logical_destination_port uuid RW, all None CR Neutron destination port.
l7_parameters dict RW, all Any CR Dict. of L7 parameters.

Json Port-pair create request example:

{"port_pair": {"name": "SF1",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Firewall SF instance",
       "ingress": "dace4513-24fc-4fae-af4b-321c5e2eb3d1",
       "egress": "aef3478a-4a56-2a6e-cd3a-9dee4e2ec345",
   }
}

{"port_pair":  {"name": "SF2",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Loadbalancer SF instance",
       "ingress": "797f899e-73d4-11e5-b392-2c27d72acb4c",
       "egress": "797f899e-73d4-11e5-b392-2c27d72acb4c",
   }
}

Json Port-pair create response example:

{"port_pair": {"name": "SF1",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Firewall SF instance",
       "ingress": "dace4513-24fc-4fae-af4b-321c5e2eb3d1",
       "egress": "aef3478a-4a56-2a6e-cd3a-9dee4e2ec345",
       "id": "78dcd363-fc23-aeb6-f44b-56dc5e2fb3ae",
   }
 }

{"port_pair":  {"name": "SF2",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Loadbalancer SF instance",
       "ingress": "797f899e-73d4-11e5-b392-2c27d72acb4c",
       "egress": "797f899e-73d4-11e5-b392-2c27d72acb4c",
       "id": "d11e9190-73d4-11e5-b392-2c27d72acb4c"
   }
}

Json Port Pair Group create request example:

{"port_pair_group": {"name": "Firewall_PortPairGroup",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Grouping Firewall SF instances",
       "port_pairs": [
           "78dcd363-fc23-aeb6-f44b-56dc5e2fb3ae"
       ],
       "port_pair_group_parameters": [
           "lb_fields: ip_src"
       ]
   }
 }

{"port_pair_group": {"name": "Loadbalancer_PortPairGroup",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Grouping Loadbalancer SF instances",
       "port_pairs": [
           "d11e9190-73d4-11e5-b392-2c27d72acb4c"
       ]
       "port_pair_group_parameters": [
           "lb_fields: ip_src"
       ]
   }
}

Json Port Pair Group create response example:

{"port_pair_group": {"name": "Firewall_PortPairGroup",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Grouping Firewall SF instances",
       "port_pairs": [
           "78dcd363-fc23-aeb6-f44b-56dc5e2fb3ae
       ],
       "port_pair_group_parameters": [
           "lb_fields: ip_src"
       ]
       "id": "4512d643-24fc-4fae-af4b-321c5e2eb3d1",
   }
}

{"port_pair_group":  {"name": "Loadbalancer_PortPairGroup",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Grouping Loadbalancer SF instances",
       "port_pairs": [
           "d11e9190-73d4-11e5-b392-2c27d72acb4c"
       ],
       "port_pair_group_parameters": [
           "lb_fields: ip_src"
       ]
       "id": "4a634d49-76dc-4fae-af4b-321c5e23d651",
   }
}

Json Flow Classifier create request example:

{"flow_classifier": {"name": "FC1",
       "project_id": "1814726e2d22407b8ca76db5e567dcf1",
       "description": "Flow rule for classifying TCP traffic",
       "protocol": "TCP",
       "source_port_range_min": 22, "source_port_range_max": 4000,
       "destination_port_range_min": 80, "destination_port_range_max": 80,
       "source_ip_prefix": null, "destination_ip_prefix": "22.12.34.45"
   }
}

{"flow_classifier": {"name": "FC2",
       "project_id": "1814726e2d22407b8ca76db5e567dcf1",
       "description": "Flow rule for classifying UDP traffic",
       "protocol": "UDP",
       "source_port_range_min": 22, "source_port_range_max": 22,
       "destination_port_range_min": 80, "destination_port_range_max": 80,
       "source_ip_prefix": null, "destination_ip_prefix": "22.12.34.45"
   }
}

Json Flow Classifier create response example:

{"flow_classifier": {"name": "FC1",
       "project_id": "1814726e2d22407b8ca76db5e567dcf1",
       "description": "Flow rule for classifying TCP traffic",
       "protocol": "TCP",
       "source_port_range_min": 22, "source_port_range_max": 4000,
       "destination_port_range_min": 80, "destination_port_range_max": 80,
       "source_ip_prefix": null , "destination_ip_prefix": "22.12.34.45",
       "id": "4a334cd4-fe9c-4fae-af4b-321c5e2eb051"
   }
}

{"flow_classifier": {"name": "FC2",
       "project_id": "1814726e2d22407b8ca76db5e567dcf1",
       "description": "Flow rule for classifying UDP traffic",
       "protocol": "UDP",
       "source_port_range_min": 22, "source_port_range_max": 22,
       "destination_port_range_min": 80, "destination_port_range_max": 80,
       "source_ip_prefix": null , "destination_ip_prefix": "22.12.34.45",
       "id": "105a4b0a-73d6-11e5-b392-2c27d72acb4c"
   }
}

Json Port Chain create request example:

{"port_chain": {"name": "PC1",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Steering TCP and UDP traffic first to Firewall and then to Loadbalancer",
       "flow_classifiers": [
           "4a334cd4-fe9c-4fae-af4b-321c5e2eb051",
           "105a4b0a-73d6-11e5-b392-2c27d72acb4c"
       ],
       "port_pair_groups": [
           "4512d643-24fc-4fae-af4b-321c5e2eb3d1",
           "4a634d49-76dc-4fae-af4b-321c5e23d651"
       ],
       "chain_id": "10034"
   }
}

Json Port Chain create response example:

{"port_chain": {"name": "PC1",
       "project_id": "d382007aa9904763a801f68ecf065cf5",
       "description": "Steering TCP and UDP traffic first to Firewall and then to Loadbalancer",
       "flow_classifiers": [
           "4a334cd4-fe9c-4fae-af4b-321c5e2eb051",
           "105a4b0a-73d6-11e5-b392-2c27d72acb4c"
       ],
       "port_pair_groups": [
           "4512d643-24fc-4fae-af4b-321c5e2eb3d1",
           "4a634d49-76dc-4fae-af4b-321c5e23d651"
       ],
       "chain_id": "10034",
       "id": "1278dcd4-459f-62ed-754b-87fc5e4a6751"
   }
}

Implementation

Assignee(s)

Authors of the Specification and Primary contributors:
Other contributors:
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