Current Meeting Report

2.6.3 IP over Optical (ipo)

NOTE: This charter is a snapshot of the 52nd IETF Meeting in Salt Lake City, Utah USA. It may now be out-of-date. Last Modified: 12-Oct-01
James Luciani <>
Daniel Awduche <>
Sub-IP Area Director(s):
Scott Bradner <>
Bert Wijnen <>
Sub-IP Area Advisor:
Scott Bradner <>
Technical Advisor(s):
Thomas Narten <>
Mailing Lists:
To Subscribe:
Description of Working Group:
The advent of switched multi-channel (e.g., WDM, DWDM, OTDM) optical networks using OXCs (Optical Cross-connects) and other optical switching elements presents many new opportunities for improving the performance of IP networks and supporting faster and more flexible provisioning of IP services. However, much needs to be specified before interoperable products based on these technologies can be deployed in service provider networks. The work needed in this area includes:

- Document the use of existing framing methods for IP over optical dataplane and control channels, and as necessary specify additional framing methods.

- Identify and document the characteristics of the optical transport network that are important for selecting paths for optical channels, setting-up optical channels, and tearing-down optical channels.

- Document the applications of the common control and measurement protocols to the technology-dependent aspects of optical path setup, teardown, and maintenance of optical channels across networks with optical components.

- Document the requirements for control of optical networks by elements outside the optical network itself.

- Document the applicability of IP-based protocols for the controlled dissemination of optical network topology, metric, and constraint information. Such information can be used for inventory management, path selection, and other purposes. The information to be exchanged should accommodate both all-optical and optical-electrical-optical switching technologies.

- If a need is identified to develop new protocols or make incompatible modifications to existing protocols (e.g., routing and signaling protocols) to accomplish the above goals, then a recharter must first be approved before undertaking such work.

The IP over Optical WG will coordinate with relevant working groups within the IETF to leverage existing work. The WG may also generate requirements for other IETF WGs as needed. Additionally, the WG may collaborate with other standards bodies and interoperability forums engaged in IP over optical activities (e.g., including ITU-T) to share information, minimize duplication of effort, and coordinate activities in order to promote interoperability and serve the best interest of the industry.

Goals and Milestones:
Mar 01   Produce Framework document with adequate motivation and detailed description of the context and solution space for IP/optical.
Aug 01   Submit I-D on 'carrier optical services' requirements for IP/Optical networks.
Aug 01   Submit I-D on the unique features of optical networks that are relevant for path computation and signaling in IP/Optical contexts.
Apr 02   Submit I-D on the Traffic Engineering issues that are specific to IP/Optical networks, which take into account the peculiar characteristics of the operating environment, including aspects of protection/restoration unique to IP/optical.
Apr 02   Submit I-D on the requirements for distribution of optical topology state information using the common control and measurement protocols.
Apr 02   Submit I-D on the requirements for signaling in IP/Optical networks using IP signaling protocols.
Dec 02   Submit applicability statements describing the use of IP based protocols for signaling and dissemination of network topology state information in IP/Optical networks.
Dec 02   Document existing encapsulation schemes for IP/optical data plane and control plane channels.
Dec 02   Submit Framework draft to IESG as a informational RFC.
No Request For Comments

Current Meeting Report

MINUTES OF IETF IP-Over-Optical (IPO) WG MEETING AT IETF-52, December 11, 2001
Salt Lake City, Utah

Jim Luciani (
Daniel Awduche (

*Thanks to Jen Yates and Sudheer Dharanikota for taking the minutes.

Meeting commenced at 5:00 PM, on 11th December 2001.

Opening remarks
Speaker: Jim Luciani
Jim presented the Agenda for the meeting and a status report on the working group.

IPO document status report

* Framework draft, has met March 2001 milestone. Intention is to perform WG last call and push to IESG for informational RFC by 4/2002.

* Carrier optical services draft, met August 2001 milestone. Push to IESG as an informational RFC by 4/2002.

* Optical impairments draft, met August 2001 milestone. Push to IESG as informational RFC by 4/2002.

* TE engineering issues (particular emphasis on IP / optical restoration), aim to submit: 4/02. IESG as informational RFC 12/02

* Distribution of optical topology state info. (particular impairment information), aim to submit: 4/02. Volunteers called for. IESG as informational RFC 12/02

* Applicability statements (applicability of CCAMP GMPLS work in IPO, particularly routing and signaling protocols), aim to submit: 4/02. Volunteers called for. IESG as informational RFC 12/02

* draft-ietf-ipo-ason. IESG as an informational RFC. Ongoing work with ITU

* draft-ietf-ipo-optical-inter-domain. IESG as an informational RFC 8/02

No questions were raised regarding the WG status report.

Carrier optical services requirements
Speaker: Ananth Nagarajan

* Draft information:
- Document describes carrier requirements for optical networks.
- Draft was a consolidation of three drafts and was discussed at London meeting
- No update has recently been submitted to IETF on this draft.
- Team waiting for ITU-T ASON and OIF NNI work to refine requirements.
- Team decided to postpone the new revision after this IETF meeting due to resource and time constraints.
* Changes:
- Significant editorial changes to improve the readability of the document.
- Incorporate ITU ASON and OIF NNI requirements.
* Plan
- Submit second version of document in January 2002.
- Publish another revision before March IETF meeting
- Last call after this.

No questions were raised concerning this work.

Impairments / constraints on optical layer routing
Angela Chiu

* Second version of this document.
* Draft information
- Document describes aspects of optical networks that impact routing and identifies possible GMPLS implications.
- Main updates in this version on impairment constraints in all-optical networks.
* Material
- Detailed presentation on document content / changes. Some summary points:
* Philosophy: let OTS design take care of impairments as much as possible - reduce overheads on routing protocols. Examined Polarization Mode Dispersion (PMD) and Amplified Spontaneous Emission (ASE).
* Additional link-specific state info to be considered by routing algorithm.
* Added text to clarify that treating each impairment separately may result in stricter constraints than if parameters considered together.
* Interworking between transparent domains (OEO in between): detailed discussion on routing algorithm sensitive to island transitions and to connectivity limitations and impairment constraints particular to each island. Information about island boundaries needs to be advertised.
* Would like to go to last call after this meeting.
* Will address comments from this WG meeting and mailing list before sending to last call.
* Will also incorporate requirements into other related documents, such as GMPLS and interdomain routing.

* Eve Varma: lots of work within ITU (OTN) on domain transparency (G.709 work). Assumes OEO at boundaries to network (clients), optically transparent within network. Work started on analogue impairments, digital impairments at client (detecting / correlating BER degradations with optical impairments). Determining which impairments need examination, and which ones can be monitored in service. This same work could be useful in application to routing impairments. Proposal: should attempt to coordinate with the IETF work with the ITU work before going to last call.
* Angela: asked if Eve can send link to document to mailing list.
* Angela: is maintenance outside scope of this document?
* Jim Luiciani: yes. May need new document to look into this.
* Daniel Awduche: work focused on real-time connection routing with IP-based control plane. A key question is how to abstract this knowledge so as to represent pertinent routing constraint information in a generic way for path computation.

Optical Inter Domain Routing Considerations
Greg Bernstein

* Document changes
- Significant improvements since last version of document:
* Basic concept of domains and network partitioning
* Major differences between optical and IP datagram routing
* Intra-carrier applications (scalability, vendor)
* Existing routing protocol applicability (OSPF, IS-IS and integrated IS-IS, BDP, PNNI)
- New material added since last version of document:
* Routing information categorization - link and topology related information, domain and node related information.
- More emphasis on:
* Single carrier case (emphasis on metro-core-metro, multi-vendor in backbone)
* Clear boundaries between domains (boundary on the wire vs boundary on the node)
* Diversity support - diverse services, network reliability
* Future changes to the document - more technical work and editing needed on:
- Applications - more detail
- Information to be shared and why... e.g. diversity services
- Drop routing analysis section
* Update on similar work within other standards / interoperability bodies
- OIF:
* New NNI work project (metro-core-metro and multi-vendor backbone).
- ITU:
* Routing work has started for G.ASON (G.RTG). Will be collaborating with ITU

* Dimitri Papadimitriou: What do you plan to do with this IETF document?
* Greg Bernstein: not chartered to define protocol. This is requirements / key drivers document. Focusing on why do carriers partition networks into domain, what they want to do with them etc. Not IPO's job to focus on protocols.

Closing remarks
* Framework draft: last call following meeting. IESG for informational RFC 4/02.
* Carrier optical services requirements: 2 iterations prior to next meeting. Short WG last call before 4/02. IESG last call 4/02.
* Optical impairments draft. WG last call 1 month after meeting. IESG last call 4/02.
* Work not yet started:
- Submit traffic engineering issues related to IPO: 4/02
- Submit requirements for distribution of optical topology state info. 4/02
- Submit applicability statements 4/02.
- Need volunteers to to write above documents. Interested volunteers can email chairs.


Impairments And Other Constraints On Optical Layer Routing
Carrier Optical Services Requirements
Optical Inter-Domain Routing Considerations
IPO Milestones