Resilient Ethernet September 2008

Resilient Ethernet: What is it? Resilient definition: “ tending to recover or adjust from misfortune” In the case of Ethernet, “misfortune” is congestion Resilient Ethernet Buffering to minimize or eliminate packet loss during temporary congestion Extensive traffic management to maintain QoS Does not require: Carrier Ethernet standards OAM Scalability

Resilient definition:

“ tending to recover or adjust from misfortune”

In the case of Ethernet, “misfortune” is congestion

Resilient Ethernet

Buffering to minimize or eliminate packet loss during temporary congestion

Extensive traffic management to maintain QoS

Does not require:

Carrier Ethernet standards

OAM

Scalability

Tools of Resilient Ethernet Extensive traffic management CIR/EIR CBS/EBS ingress policing Police per port, EVC, traffic-class per EVC Deep buffering Internal buffering (dedicated) typically at <1MB At 10Gbps rates: 80us of temporary congestion – no packet loss External buffering (dynamic) at ~200MB At 10Gbps rates: >100ms of temporary congestion - no packet loss Congestion avoidance Congestion avoidance per output queue WREDTail Drop with configurable thresholds EIR CIR 100Mb 400Mb

Extensive traffic management

CIR/EIR CBS/EBS ingress policing

Police per port, EVC, traffic-class per EVC

Deep buffering

Internal buffering (dedicated) typically at <1MB

At 10Gbps rates: 80us of temporary congestion – no packet loss

External buffering (dynamic) at ~200MB

At 10Gbps rates: >100ms of temporary congestion - no packet loss

Congestion avoidance

Congestion avoidance per output queue

WREDTail Drop with configurable thresholds

Resilient Ethernet Application Multiple processors or IO connected through L2 Ethernet fabric Unpredictable traffic Random congestion at each port Potential Applications VoD Servers, IPTV platforms, multi-protocol transport SPI4.2 10GE Uplinks GbE Ports 10GE MAC CPU CPU CPU IO IO

Multiple processors or IO connected through L2 Ethernet fabric

Unpredictable traffic

Random congestion at each port

Potential Applications

VoD Servers, IPTV platforms, multi-protocol transport

Enterprise Switch Operation 500Mbps burst on one port penalizes other traffic for the congested port Goal is to penalize the “bursty” port only Possible solutions Move to 10GE links Enterprise Switch All ports penalized RESILIENT ETHERNET

500Mbps burst on one port penalizes other traffic for the congested port

Goal is to penalize the “bursty” port only

Possible solutions

Move to 10GE links

Resilient Ethernet Operation Bursty port does not penalize well-behaved traffic Penalty for the “bursty” port is gradual Temporary over-subscription: Packets are stored in deep buffers Long-term over-subscription: “Green” guaranteed, “Yellow” dropped WRED is designed specifically for bursty traffic Averages queue depths so that only sustained oversubscription causes drops. Deep packet buffers are required to run WRED effectively (Only bursty port penalized)

Bursty port does not penalize well-behaved traffic

Penalty for the “bursty” port is gradual

Temporary over-subscription: Packets are stored in deep buffers

Long-term over-subscription: “Green” guaranteed, “Yellow” dropped

WRED is designed specifically for bursty traffic

Averages queue depths so that only sustained oversubscription causes drops.

Deep packet buffers are required to run WRED effectively

Summary Resilient Ethernet is required in many triple play applications Unpredictable and wide range of traffic patterns Brooklyn-10 is architected to provide Resilient Ethernet switching through: Carrier-grade QoS features such as policing & congestion avoidance Deep buffers for true WRED operation Well-behaved ports are NEVER penalized Penalty for the “bursty” port is gradual

Resilient Ethernet is required in many triple play applications

Unpredictable and wide range of traffic patterns

Brooklyn-10 is architected to provide Resilient Ethernet switching through:

Carrier-grade QoS features such as policing & congestion avoidance

Deep buffers for true WRED operation

Well-behaved ports are NEVER penalized

Penalty for the “bursty” port is gradual

More Information Available Lightstorm website http://www.lightstormnetworks.com/ Sign up for Extranet access to get latest product briefs, functional specifications, data sheets, etc. http://www.lightstormnetworks.com/xtranet/login.asp ?

Lightstorm website

http://www.lightstormnetworks.com/

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