Policy aware frame loss measurement

A method of measuring frame loss for use at ingress to a network, said method comprising the steps of:

• preparing a measurement frame to be transmitted over said network;
• deciding an action to take on said measurement frame in accordance with a decision value calculated according to the current status of an ingress policer;
• if said decision is to drop said measurement frame then
• randomly deciding a marking decision in accordance with the ratio between configured committed information rate (CIR) and excess information rate (EIR);
• marking said measurement frame in accordance with said marking decision;
• and
• otherwise marking said measurement frame in accordance with said decision.

A method of measuring frame loss for use in the middle of a network, said method comprising the steps of:

• maintaining a committed information rate (CIR) counter and an excess information rate (EIR) counter;
• receiving a measurement frame over said network at a middle policer;
• applying color aware policing to said measurement frame in accordance with a service level agreement (SLA) and generating a policer decision based thereon;
• not dropping said measurement frame regardless of the policer decision made by said middle policer;
• setting one or more flags in a flags field within said measurement frame in accordance with said policer decision;
• and
• forwarding said measurement frame over said network in accordance with a forwarding flag regardless of the policer decision made by the middle policer.

A provider edge switch for use at the ingress to an Ethernet based network, comprising:

• a plurality of line cards incorporating one or more ports for interfacing said provider edge switch to one or more users, each line card comprising:
• a plurality of ports, each port coupled to a communication link;
• a packet processing engine coupled to said plurality of ports, said packet processing engine for determining forwarding decision and destination queue for each ingress packet;
• a queue manager coupled to said packet processing engine;
• a loss measurement module for measuring frame loss for Transparent LAN Services (TLS) connections in a metro Ethernet network (MEN), said loss measurement module comprising:
• maintaining a committed information rate (CIR) counter and an excess information rate (EIR) counter;
• preparing a measurement frame to be sent over said network;
• calculating a ratio of CIR to EIR traffic;
• randomly deciding a marking decision in accordance with said ratio;
• marking said measurement frame in accordance with said marking decision;
• and
• switching means coupled to said queue manager and adapted to provide switching fabric functionality to said provider edge switch.

A provider edge switch for use at the ingress to an Ethernet based network, comprising:

• a plurality of line cards incorporating one or more ports for interfacing said provider edge switch to one or more users, each line card comprising:
• a plurality of ports, each port coupled to a communication link;
• a packet processing engine coupled to said plurality of ports, said packet processing engine for determining forwarding decision and destination queue for each ingress packet;
• a queue manager coupled to said packet processing engine;
• a loss measurement module for measuring frame loss for a plurality of connections in a metro Ethernet network (MEN), said loss measurement module comprising:
• maintaining a committed information rate (CIR) counter and an excess information rate (EIR) counter;
• preparing a measurement frame to be sent over said network;
• deciding an action to take on said frame in accordance with a decision value calculated according to the current status of an ingress policer;
• if said decision is to drop said measurement frame then randomly deciding a marking decision in accordance with the ratio between the configured CIR and EIR, marking said measurement frame in accordance with said marking decision;
• otherwise marking said measurement frame in accordance with said decision;
• and
• switching means coupled to said queue manager and adapted to provide switching fabric functionality to said provider edge switch.

A provider core switch for use in the middle of an Ethernet based network, comprising:

• a plurality of line cards incorporating one or more ports for interfacing said provider switch to other provider switches, each line card comprising:
• a plurality of ports, each port coupled to a network communications link;
• a packet processing engine coupled to said plurality of ports, said packet processing engine for determining forwarding decision and destination queue for each ingress packet, said packet processing engine comprising a middle policer;
• a queue manager coupled to said packet processing engine;
• a loss measurement module for measuring frame loss for a plurality of connections in a metro Ethernet network (MEN), said loss measurement module comprising:
• receiving a measurement frame over said network;
• applying color aware policing by said middle policer to said measurement frame in accordance with a service level agreement (SLA) and generating a policer decision based thereon;
• not dropping said measurement frame regardless of the policer decision made by the middle policer;
• setting one or more flags in a flags field within said measurement frame in accordance with said policer decision;
• forwarding said measurement frame over said network in accordance with a forwarding flag regardless of the policer decision made by the middle policer;
• and
• switching means coupled to said queue manager and adapted to provide switching fabric functionality to said provider core switch.