IETF-68, IETF ECRIT / IEEE Joint Meeting1

1
Various updates on LLDP (IEEE 802.1AB) and
LLDP-MED (ANSI/TIA-1057)

• Peter Blatherwick
• Dan Romascanu
• IETF-68, IETF ECRIT / IEEE Joint Meeting

2
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

3
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)

4
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

5
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)

6
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?

7

• Backup Material

8
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 LLDPs 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

9
How LLDP / LLDP-MED Works (10,000 m view)

• 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)

10
LLDP-MED Content