a survey on interlaken protocol for network applications department of computer science and...

A Survey on Interlaken Protocol for Network Applications

Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan, R.O.C.

Authors: Gaidhani Dhananjay Shekhar, A.Yogaraj.

Publisher: International Journal on Recent and Innovation Trends in Computing and Communication (IJRITCC) 2015

Presenter: Chun-Yu, Li

Date: 2015/9/30

Outline

Introduction• Technology Evolution• SPI4.2• XAUI

Interlaken Protocol• Design Goals• Highlights of Interlaken Protocol

Existing Work• Implementation History• Summary of Various IPs

Computer & Internet Architecture Lab CSIE NCKU

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Technology Evolution (1/3)

Components with gigabit-scale throughput traditionally have data buses running about 100Mbps per pin.

Differential signaling technology enables components with throughput on the order of 10Gbps.

New serial technology with clock and data recovery enables components with multiple of 100Gbps.


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Interlaken was invented by Cisco Systems. It is an interconnect protocol optimized for high-

bandwidth and reliable packet transfer. It works as an interface between 1st and 2nd layer of

OSI model. It takes advantages of two dominant high-speed chip-

to-chip interface.• SPI4.2• XAUI


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Outline





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SPI4.2 (1/3)

SPI4.2 is a protocol used for data transfer between link layer device and physical layer device.

It is published by the Optical Internetworking Forum. It aggregate bandwidths of OC192 ATM and packet

over SONET (Synchronous Optical Networking), as well as for 10 Gb/s Ethernet applications.


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SPI4.2 (2/3)

On both the transmit and receive interfaces, FIFO status is sent separately from the corresponding data path.


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SPI4.2 (3/3)

Point-to-Point connection (i.e. between single PHY & single Link Layer device),

Support for 256 ports, Transmit & Receive data path is 16 bit, Channelization, programmable burst size & per-

channel back pressure.


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Outline





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XAUI (1/3)

It is developed by IEEE 802.3ae 10 Gigabit Ethernet Task Force.

XAUI is a standard for extending the XGMII between the MAC and PHY layer of 10 Gigabit Ethernet.

XGMII (10 Gigabit Media Independent Interface) • Provides a 10 Gb/s differential signal pipeline.• The separate transmission of clock and data coupled.• Its timing requirement to latch data on both the rising and

falling edges of the clock.• Which result in significant challenge in routing the bus more

than the recommended short distance of 7 cm.


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XAUI (2/3)


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XGXS: XGMII Extender Sublayer

XAUI (3/3)


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It is a narrow 4-lane interface, offers long reach, Independent transmit and receive data paths, Differential signaling with low voltage swing, Utilization of 8b/10b encoding, It suits a variety of implementations like FR4 on

PCB, backplanes & cables, As a packet-based interface it lacks channelization &

flow control.

Outline





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Design Goals (1/13)


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Bandwidth Range• Interlaken should not have specific upper limit. It

is primarily targeted for 10Gbps to 100Gbps. Scalability

• The following two parameters determine the connection bandwidth:• Number of serial lanes in the interface,• Frequency of each lane.

Design Goals (2/13)


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Number of serial lanes in the interface• The effective bandwidth of Interlaken protocol

corresponds to the number of lanes on which it is working.

Design Goals (3/13)


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Frequency of each lane• Effective bandwidth also scales directly with the

per-lane bit rate. • For example, a 3.125 Gbps port can carry half the

payload of a 6.25 Gbps.

Design Goals (4/13)


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Since bandwidth can be increased by either adding more lanes or by increasing the bit rate per lane, Interlaken is a very scalable interface.

Design Goals (5/13)


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Flexibility• ICs with different capacities in a single physical

interface can be split up into multiple lower-speed physical interfaces.

Design Goals (6/13)


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Channelization• To support varying number of channels Interlaken

should have support to operate on different number of channels available for the particular application.

There are two basic methods of sending packets across an interface:• Non-interleaved Transfers,• Interleaved Transfers.

Design Goals (7/13)


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Non-interleaved Transfers• The transfer of a packet is always completed

before transfers are started on another channel.

Design Goals (8/13)


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Interleaved Transfers• Each channel transmits only a small fragment

(burst) of a packet before moving to the next channel.

Design Goals (9/13)


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Burst control word with channel field.• Applications that support to 64 K channels by

using the dual-use field combined with the normal 8-bit channel field.

Design Goals (10/13)


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Resiliency• Use of strong cyclic redundancy check (CRC) and

technology known as scrambling. • The health of each serial link is continuously and

transparently monitored.



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Burst CRC24 Coverage



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SerDes (Serializer/Deserializer) lanes would make it difficult to ensure that errored packets could be adequately detected.



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Scrambling• Since Interlaken uses a scrambler, there must be a

methodology to synchronize the receiver to the scrambler-state.

• The receiver uses the recovered scrambler-state to synchronize its scrambler and then de-scramble the data stream.

• E.g. Linear Feedback Shift Register (LFSR)

Outline





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Highlights of Interlaken Protocol (1/1)

Support for 256 communications channels, or up to 64K with channel extension.

A simple control word structure to delineate packets, similar in function to SPI4.2.

Protocol independence from the number of SerDes lanes and SerDes rates.

64B/67B data encoding and scrambling. Performance that scales with the number of

lanes.


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Outline





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Implementation History (1/1)


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Outline





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Summary of Various IPs (1/1)


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a survey on interlaken protocol for network applications department of computer science and...

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