BBF WT-474 compliant Subscriber Session Steering (SSS) server

a python based User Plane Service Function (UPSF) gRPC server implementation. The server is lightweight by design and contains not much logic, as the i.e. 'decision logic where a session would be assigned to' should be done by a operator. Only trivial operations like checks if a item already exists before i.e creating/updating. Items are uniquely identified by its name which is mandatory on creation. Only session contexts don't need a name on creation as the name is a hash generated by the provided 5-tuple (s-tag, c-tag, source-mac-address, remode-id, circuit-id).

Prerequisites

• redis
• python3
• pip
• virtualenv (optional)
• python packages from requirements.txt pip install -r requirements.txt

python3 setup.py build install

Run the server

in order to run the server start the redis server and point to the host / port where the redis server is running. This can be done by setting ENV vars or using cmd line options, please refer to the section below.

upsf-server [flags]

where flags are:

• flags: Specifies optional flags. For example, you can use the --redis-host flag to specify the address of the redis server.

Config options

option	flag	description	default
NAME	--name	the name of the server	upsf-server
GRPC_MAX_WORKERS	--max-workers, --grpc-max-workers	the maximum count of active gRPC worker threads	16
GRPC_BIND_ADDR	--bind-addr, --grpc-bind-addr	the bind address of the gRPC host	[::]
GRPC_BIND_PORT	--bind-port, --grpc-bind-port	the bound port of the gRPC port	50051
REDIS_HOST	--redis-host	the host address of the redis backend	127.0.0.1
REDIS_PORT	--redis-port	the host port of the redis backend	6379
REDIS_PASSWORD	--redis-password	the password of the redis backend	None
REDIS_HEALTH_CHECK_INTERVAL	--redis-health-check-interval	the redis health check interval	30
DEFAULT_SHARD_NAME	--default-shard	default subscriber group (shard) to assign to new session context on failed sss lookups	default-shard
UPSF_CMD_QUEUE	--upsf-cmd-queue	the Redis cmd queue to listen to	UpdatesIngress
UPSF_CMD_QUEUE_AUTO_PROCESS	--upsf-cmd-queue-auto-process	bool to enable or disable the command queue	True
LOGLEVEL	-l, --loglevel	the level of information printed. Available options: info, warning, critical, error, debug	info

Note: the UPSF cmd queue can be invoked to process each item by a special operator which may have individual logic for each item type.

gRPC services

for a list of available message contents please refer to the .proto files located in the protos directory.

RPC	item	return	description
CreateV1	wt474_messages.v1.Item	wt474_messages.v1.Item	creates a new item
UpdateV1	UpdateReq	wt474_messages.v1.Item	updates an item
DeleteV1	google.protobuf.StringValue	google.protobuf.StringValue	deletes an item
LookupV1	wt474_messages.v1.SessionContext.Spec	wt474_messages.v1.SessionContext	looks up a session context by the provided 5-tuple (mentioned above) or creates one on the fly
ReadV1	ReadReq	stream wt474_messages.v1.Item	ReadReq allows one or more items to be retrieved

ReadV1 Notes:

All items of one type can be retrieved by omitting the parent A single item of itemtype can be retrieved by specifying the itemname as parentname. Otherwise, all items of a defined type recursively 'under' the parent will be returned. This includes where an item is 'under' the parent through a desired or current field. When the 'watch' flag is not set, the stream will close after all current items matching the request have been sent. When the 'watch' flag is set, the stream will remain open to send any further changes to any items matching the request.