Standardizing MRT IETF 61 - GROW November 9, 2004 1

Standardizing the MRT format

Larry J. Blunk, Merit NetworkIETF 61

Washington, DCNovember 9, 2004

Standardizing MRT IETF 61 - GROW November 9, 2004 2

MRT BackgroundWhy StandardizeBasic FormatExisting Type DefinitionsImplementationsIssues

Overview

Standardizing MRT IETF 61 - GROW November 9, 2004 3

MRT format developed as part of the Multi-threaded Routing Toolkit at Merit in mid-90'sSimple format to record routing information with timestamps

Routing messages/packets (e.g. BGP UPDATEs)RIB table dumps

Primarily used for BGP informationAlso can support other routing protocols (e.g. RIP, RIPng, OSPF, ISIS)

MRT Background

Standardizing MRT IETF 61 - GROW November 9, 2004 4

Why standardize?

The MRT format is widely used by researchers studying BGP and Inter-domain routingEmployed by RIPE RIS and Routeviews BGP routing data collectorsExisting documentation of MRT format is limitedThere are a now 9+ implementations

Some implementations have compatibility issuesResearchers and vendors have duplicated efforts in some cases to extend the formatCurrently no method to avoid conflicts when extending

Standardizing routing information export format would seem to complement work in IPFIX for IP flows

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Basic MRT Format

0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Timestamp |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Type | Subtype |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Length |+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+| Message... (variable)+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Initial draft - http://www.mrtd.net/doc/mrt-draft-00.html

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Existing Type Definitions

Control TypesNULL, START, DIE, I_AM_DEAD, PEER_DOWNProvides indication/timestamps when a MRT data collection begins and ends, and loss of connectivity to a peerNo known implementation support

Routing Information TypesBGP, RIP, IDRP, RIPNG, BGP4PLUS, BGP4PLUS_01, OSPF, TABLE_DUMPZebra created new BGP4MP type which combines capabilities for BGP, BGP4PLUS, BGP4PLUS_01, and TABLE_DUMP types under a single typeSprint Labs has created a type for ISIS informationSome undocumented vendor types – Arbor, Packet Design

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Implementations

Routing daemonsMRTdZebra/QuaggaOpenBSD BGPD

ToolsMRT routebtoa/routeatob – ascii dumper/undumperlibbgpdump – library package and bgpdump utilityzebra-dump-parser – perl based dumperC-BGP – BGP decision process simulatorpyrt - Sprint Labs Python Routing Toolkit

Internal product implementations by vendorsArbor NetworksPacket Design

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Issues

Existing MRT implementations rely on local storage of data

Transport mechanisms for devices without storage, like routers, have not been throughly addressed

The specification includes support for RIP, RIPng, and OSPF, but these formats have not been fully documented nor implemented – e.g., need should format include source/dest IP addressesSome conflicts exist between implementations

Need mechanisms to extend format and avoid conflicts

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Issues (cont'd)

Existing format uses timing resolution of one secondSprint and Packet Design have added support for sub-second resolution – may wish to standardize support

Possible new formats to aggregate or refine information

Summarization by prefix or AS may be usefulShould there be a requirements document?Is the current basic format sufficient to meet future needs?