Various updates on

LLDP (IEEE 802.1AB) and

LLDP-MED (ANSI/TIA-1057)

Peter Blatherwick

Dan Romascanu

IETF-68, IETF ECRIT / IEEE Joint Meeting

Caveat

• This is not a formal liaison or anything like it– Peter Blatherwick: “just a guy who happens to be Editor of LLDP-MED

(ANSI/TIA-1057)”

– Dan Romascanu: “just a guy who happens to attend IEEE 802.1”

TIA TR-41.4 Status, LLDP-MED & ECS

• ANSI/TIA-1057, Link Layer Discovery Protocol for Media Endpoint Devices (LLDP-MED)– Provides VoIP extensions to IEEE 802.1AB LLDP, including endpoint location (and lots more)

– Published April 2006

– No currently active project in TR-41.4

• TSB-146-A, IP Telephony Support for Emergency Calling Service (2nd revision)– Provides informational overview and possible usages of relevant technologies for device

location and other ECS needs, including LLDP-MED, DHCP-based, SNMP-based, WLAN scenarios

– Publication pending

• TR-41.4 liaison with NENA– Responding to NENA requirements TRs (in progress) almost all NENA location requirements

well met by LLDP-MED, some cannot be realistically met by any location method

• Possible LLDP-MED extensions talked about (not committed to)– Ability to support location by reference and/or delivery of PIDF-LO objects directly

– Ability to indicate location determination method used (manual, GPS, triangulated, etc)

– Ability to indicate ECS call in progress

– Possible relay/forwarding mechanisms to provide end device with LLDP-MED location, independent of the access network mechanism in use (could be DHCP, L7 LCP, network-specific / proprietary …)

– Support for device-specific location in WLAN environments (note: LLDP-MED supports AP-specific location today)

IEEE 802.1ABrev

• Revision of IEEE 802.1AB – LLDP – PAR approved November 2006

• New information elements and a mechanism for faster exchange of information (‘fast start’) for early exchange of capabilities

– Similar to and compatible with LLDP-MED ‘Fast Start’ (some open questions)– Mainly to support layer 2 Congestion Management and Audio-Video Bridging– Can also be used to push location information (same as LLDP-MED today)

• New destination addresses and explicit forwarding rules to accurately define the topology over transparent forwarding devices like the ones defined by IEEE 802.1ad (provider bridges) and 802.1aj (two-port media relays – TPMR)

– Breaks the original assumption that all LLDP devices are connected on the same media (LLDP-MED would remain single L2 link-specific)

• Support for IEEE 802.3at (extended Power over Ethernet, “PoE Plus”)

• Liaison with TIA TR41.4– see http://www.ieee802.org/1/files/public/docs2007/liaison-to-tr41-4-0307.txt

IEEE 802.3at “PoE Plus”

• IEEE 802.3at to provide higher power PoE, with management– Many management needs aligned with LLDP-MED “Extended Power via

MDI” TLV (aka Extended PoE TLV)

– High synergy, since wired Ethernet IP Phones and other VoIP endpoints are a large category of devices, almost all using PoE

• LLDP-MED Extended PoE TLV accepted as basis for PoE management– 3 proposals at March IEEE 802.3 plenary, all use LLDP-MED data

content (unclear which accepted … meeting was just last week)

Some questions / issues for discussion

• Can IEEE 802.11 / .16 and others use LLDP-MED as the method for location acquisition in WLAN environments ??– IETF ECRIT currently references LLDP-MED as the single

method for location acquisition at Layer 2 (of 3 methods total)– Yet another method at Layer 2 would be confusing, wasteful, and

add complexity (bad)

• Requirements: – Requesting location (vs continuous update)

• What are the specific IEEE groups to work with on these topics?

Backup Material

Background

• TIA TR-41.4: – Engineering subcommittee in TIA, mandate for User Premises

Telecommunications Requirements / IP Telephony Infrastructures

• LLDP-MED (ANSI/TIA-1057):– VoIP-specific set of extensions to LLDP (IEEE 802.1AB), created by

TR-41.4

– Leverages LLDP’s excellent extensibility properties

– Defines several new TLVs (Type-Length-Value) for: – LAN Policy (Diffserv, Layer 2 Priority, VLAN)– Location Identification (IETF compatible civic and geo location, plus ELIN)– Extended Power Over Ethernet– Inventory management

– Also defines some new protocol behaviour (‘Fast Start’) and a few constrains on base LLDP

How LLDP / LLDP-MED Works (10,000 m view)

I’m an IP-Phone

I’m an IP-Phone

I’m an IP-Phone

I’m an IP-PBX

I’m a PC

I’m a switch

I’m a switch

I’m a switch

I’m a switch

I’m a switch

I’m a switch

I’m a switch

PSTN

xxxxSwitchB21

xxxxPCB6

xxxxIP-phoneA4

infodeviceport

Discovery MIB xxxxIP-PBXF3

xxxxIP-PhoneD2

xxxxIP-PhoneC2

xxxxSwitchA19

infodeviceport

Discovery MIB

Very simple / robust• Simple one-way periodic advertisement,

no Ack/Nak, command/response, etc.

• Frames contain formatted records (TLVs)

• Simple time-to-live mechanism for data aging

• “Fast Start” protocol mechanism speeds startup and initial autoconfiguration

• Data containers defined by local and remote MIBs (SNMP is not mandatory)

• Small number of mandatory TLVs, several optional TLVs are defined

Efficient and secure• Transmissions contained to individual

L2 links (not broadcast)

• Runs after 802.1X authentication, preventing unauthorized access to VoIP network

Highly extensible• Easily defined Organization Specific

TLVs (e.g. TIA, vendor-specific, etc)

• Very clear methods to define agreed data formats (local and remote MIB extensions)

Very simple / robust• Simple one-way periodic advertisement,

no Ack/Nak, command/response, etc.

• Frames contain formatted records (TLVs)

• Simple time-to-live mechanism for data aging

• “Fast Start” protocol mechanism speeds startup and initial autoconfiguration

• Data containers defined by local and remote MIBs (SNMP is not mandatory)

• Small number of mandatory TLVs, several optional TLVs are defined

Efficient and secure• Transmissions contained to individual

L2 links (not broadcast)

• Runs after 802.1X authentication, preventing unauthorized access to VoIP network

Highly extensible• Easily defined Organization Specific

TLVs (e.g. TIA, vendor-specific, etc)

• Very clear methods to define agreed data formats (local and remote MIB extensions)

LLDP-MED Content

Usage of LLDP Core SpecAll mandatory aspects of LLDP are also mandatory for LLDP-MED (chassis id, port id, time to live, end of LLDPDU)

Mandatory

Mandatory formats of Chassis ID, Port ID (LLDP has several optional types) MandatoryLLDP Capabilities TLV (Telephone, embedded L2 switch, optional in LLDP) Madnatory for Class III802.3 LAN speed and duplex TLV (optional in LLDP) Mandatory802.3 PoE extended TLV (optional in LLDP) Not recommended

LLDP-M ED ExtensionsLLDP-MED Capabilities TLV (Device Class, TLV support) MandatoryNetwork Policy TLV (LAN autoconfiguration) Mandatory

VLAN ID subtypeL2 Priority subtypeDiffserv Codepoint subtype

Location Identification TLV (supports ECS / E911 and other location services) Mandatory for Class IIIIETF Coordinate-based LCI subtypeIETF Civic Address LCI subtypeELIN subtype (E.164 formatted dialstring, for traditional E911 support))

Extended Power over Ethernet (fine grained control and prioritization) Mandatory for PoE devicesInventory Management (Device manufacturer/model/sw versions etc. 7 TLVs total) OptionalFast Start protocol behaviour Mandatory