<html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> </head> <body text="#000000" bgcolor="#FFFFFF"> <tt>Hi there,</tt>   <tt>A brief overview of what is happening in the IETF in working groups related to routing. This is not necessary a complete list, and given the proximity of upcoming IETF 103 meeting, there will be a large number of new submissions and changes to existing documents in the coming weeks. This list is built based on the state of WGs and documents just prior to RIPE 77 meeting. The goal is to provide an informal description of what is happening on the protocol and technology development, and what eventually may come to operations communities in not too distant future. </tt> <tt>The intention is to draw attention of RIPE Routing WG participants onto what is in development in the IETF, with a particular wish to bring in the comments and feedback from RIPE community into the IETF. If you see a topic being of interest and relevant to your environment, please consider reviewing the documents and providing feedback, either to the WG mailing list, to the document authors, or to WG chairs. If you would be interested in becoming more involved in IETF document review but either hesitate or are not certain what that might look like and what the time commitment would be - please reach to me either in the hallway or via mail. </tt> <tt> </tt> <tt>BABEL BABEL WG works on evolutional development of a distance vector routing protocol targeted for both robust and lossy networks, with a set of properties that result in fast convergence in case of arbitrary topology changes, possibly trading the optimality of the topology for that. - Base specification. The main focus is to move BABEL specification to a standards track from the previous experimental one, providing details on ambiguous or underspecified protocol operation aspects. Reading list: draft-ietf-babel-rfc6126bis. - BABEL over DTLS. BABEL itself does not have mechanisms for neighbour authentication and exchanged message integrity, DTLS is proposed to be used for that. Reading list: draft-ietf-babel-dtls. - Modelling and manageability. An initial work on manageability aspects of BABEL, currently defining an informational model, eventually providing a YANG data model too. Reading list: draft-ietf-babel-information-model. </tt> <tt> BESS BESS WG covers connectivity services that use BGP in one or another form for their operation – L3VPN, L2VPN, EVPN, and numerous their derivatives. At the current time the major focus is on EVPN features and extensibility, the rest of the topics are in maintenance mode. - EVPN maintenance. Multi-attachment operation, optimizations of multipoint frame distribution, service redundancy. Reading list: draft-ietf-bess-evpn-bum-procedure-updates, draft-ietf-bess-evpn-inter-subnet-forwarding. - L2VPN and L3VPN YANG models. Configuration and monitoring models for network elements providing both L2VPN and L3VPN connectivity services. Not to be confused with L2 and L3 service models. Reading list: draft-ietf-bess-l3vpn-yang, draft-ietf-bess-l2vpn-yang. </tt> <tt> BFD BFD WG focuses on evolution and extensions of BFD protocol and its applicability to various dataplanes and encapsulations. The core specification of BFD is complete and is universally deployed, the majority of the current work is on extensions required for new encapsulations and use cases. - Multipoint BFD. A mechanism that allows for BFD to validate reachability in multipoint environments. The nature of multipoint connectivity requires the introduction of different roles for BFD session head and session tails, it is no longer a fully symmetric protocol. Reading list: draft-ietf-bfd-multipoint , ietf-bfd-multipoint-active-tail. - BFD YANG models. An NMDA compatible YANG model for managing and monitoring BFD. Reading list: draft-ietf-bfd-yang. - Authentication extensions. The cost of authenticating every BFD packet makes it impractical if not completely undeployable. However, the information that would really need to be authenticated does not necessary repeat in every BFD packet, therefore it may be enough to authenticate only those BFD packets that signal a state change. Another extension is for a change on how sequence numbers are generated. Reading list: draft-ietf-bfd-optimizing-authentication, draft-ietf-bfd-secure-sequence-numbers. - Unsolicited BFD. A seemingly simpler mechanism than Seamless BFD for establishing a BFD session to an endpoint that has no specific initial session configuration. Reading list: draft-chen-bfd-unsolicited. BIER BIER WG focuses on defining a new dataplane encapsulation and a new forwarding paradigm for multipoint distribution of packets – ie, redefining multicast forwarding in a scalable and deterministic way. The core of BIER specification is complete, current work focuses on various extensions and integration with other technology components, as well as looking into usability and deployment aspects of it. - BIER specification. The core BIER specification is complete. There are extensions for various control plane components that need to be finalized. Reading list: RFC8279, RFC8296, draft-ietf-bier-evpn, draft-ietf-bier-path-mtu-discovery. - BIER integration. Not all BIER deployments will be greenfield, there is a need for interoperability mechanisms with existing multicast environments. Reading list: draft-ietf-bier-use-cases, draft-przygienda-bier-migration-options, draft-ietf-bier-pim-signaling. - BIER manageability. YANG model for configuration and monitoring of BIER nodes. Reading list: draft-ietf-bier-bier-yang. CCAMP CCAMP WG works on defining a set of control plane components for non-packet based, predominantly optical transport networks. This is a long lived WG, having completed most of the core protocol work a while ago, with the current focus being on maintenance and extensions, and a larger amount of work on manageability aspects of transport networks. - Modelling. YANG models for transport network topologies and individual connectivity features. Reading list: draft-ietf-ccamp-wson-yang, draft-ietf-ccamp-l1csm-yang, draft-ietf-ccamp-alarm-module. </tt> <tt>DETNET DETNET WG addresses the problem of deterministic operation in packet based networks where packet delivery timing and reliability have strict bounds. A relatively new WG, looking into the applicability of existing IETF technologies to time sensitive data communication systems within a bounded domain. - Overall architecture. Definition of main assumptions of how deterministic traffic flows could be mapped onto packet network infrastructure, what would the requirements be, and how those requirements could be fulfilled. Reading list: draft-ietf-detnet-architecture, draft-ietf-detnet-problem-statement, draft-ietf-detnet-use-cases. - IP and MPLS dataplanes. How IP, and MPLS and its derivatives could be applied to transport time sensitive payloads, what would be the assumptions and limitations made, and what is required for extensibility. Reading list: draft-ietf-detnet-dp-sol-ip , draft-ietf-detnet-dp-sol-mpls. - Bounded latency. A subset of new work on characterizing the total end to end latency and amount of required resources for zero loss transmission of flows. Reading list: draft-geng-detnet-requirements-bounded-latency, draft-finn-detnet-bounded-latency, </tt> <tt> I2RS I2RS WG works on defining programmatic interfaces to routing system – a way of accessing and manipulating routing information by ways other than via routing protocols. Most of the chartered work is done, there is little activity, the working group is approaching its closure, and, sadly, little of practical applicability exists in the developed mechanisms. </tt> <tt> IDR IDR WG focuses on the protocol that glues the Internet together – BGP. While the core specification of BGP has been stable for a long time, there is a large amount of extensions and new features being worked on. - Extended messages. Initially BGPsec signed path attributes, and nowadays new address families and general update packing efficiency are being affected by a limit of a BGP message size of 4096 octets. A simple mechanism allows for extending BGP messages to carry payload of up to 64K octets. Reading list: draft-ietf-idr-bgp-extended-messages. - Flowspec maintenance. A set of clarifications and fixes to the base Flowspec document RFC5575, and various optimizations for traffic matching and redirect operations. Reading list: draft-ietf-idr-rfc5575bis, draft-ietf-idr-flowspec-interfaceset, draft-ietf-idr-flowspec-path-redirect, draft-khare-idr-bgp-flowspec-payload-match. - RS BFD. A mechanism for BFD based dataplane connectivity validation, especially in route server environments. Reading list: draft-ietf-idr-rs-bfd. - New BGP communities. There are still not enough of different types of BGP communities. :-) Extended communities are not fully AS4 capable, and various VPN address families will require that. Reading list: draft-heitz-idr-extra-extended-community, draft-ietf-idr-wide-bgp-communities. - BGP autodiscovery. There appears to be an increased interest in various forms of BGP neighbour and topology discovery mechanisms, mostly targeted to densely interconnected topologies. Reading list: draft-raszuk-idr-bgp-auto-session-setup, draft-xu-idr-neighbor-autodiscovery, draft-acee-idr-lldp-peer-discovery. - Optimal reflection. Route reflectors help with overall routing information state reduction but at a cost of topology hiding, and providing one set of best paths for all clients. An extension to reflector operation allows for different clients to receive different sets of best paths. Reading list: draft-ietf-idr-bgp-optimal-route-reflection. - Route refresh extensions: Route refresh is a widely deployed mechanism and is considered to be a best practice. An extension allows for a more granular request for refreshing a specific address family or a set of prefixes or route types. Reading list: draft-idr-bgp-route-refresh-options. - BGP compression. The increase of the amount of state that needs to be transferred between the peers directly affects the amount of octets that need to be sent and received. Observing that there is a large number of repetitive patterns in BGP payload, a mechanism to bundle together and compress BGP messages is defined. Reading list: draft-przygienda-idr-compressed-updates. - Modelling. A YANG model for configuration of both BGP sessions and BGP routing policy. Reading list: draft-ietf-idr-bgp-model. </tt> <tt>LISP LISP WG works on a routing and addressing architecture that separates routing and node identification namespaces and allow for routing system scalability to extend substantially beyond current single namespace approach. Majority of core protocol work is complete, current work focuses on extensibility and implementation of LISP based connectivity services. - Core protocol maintenance. Maintenance and extensions of core LISP architectural model and control plane components. Reading list: draft-ietf-lisp-rfc6830bis, draft-ietf-lisp-rfc6833bis - Modelling. LISP YANG model for configuration and management. Reading list: draft-ietf-lisp-yang. - Mapping system evolution. Reading list: draft-ietf-lisp-pubsub. - Mapping system security. A set of mechanisms for ensuring the authentication and integrity of mapping system information. Reading list: draft-ietf-lisp-sec. </tt> <tt> LSR LSR WG focuses on evolution of IS-IS and OSPF routing protocols, it is a merger of previously separate ISIS and OSPF WGs. Majority of the work is on extensions needed for other WGs, with a new work gaining traction in defining a more scalable IGP operation in densely interconnected environments. - IS-IS over TCP. IGPs generally use their own transport mechanisms and as a result the complexity required for ensuring robust and deterministic behaviour of an IGP during the periods of synchronization of large amounts of state is both nontrivial and proprietary. Offloading a large part of that complexity to underlying reliable transport may seem to be a practical way forward, and a proposed mechanism uses TCP for point-to-point dissemination of state between IS-IS routers. Reading list: draft-hsmit-lsr-isis-flooding-over-tcp. - IGP flooding optimizations. A set of proposed mechanisms to limit the over-redundant flooding of the topology information distribution by constraining a set of links over which it gets propagated. Reading list: draft-li-dynamic-flooding, draft-cc-isis-flooding-reduction. - Flexible IGP algorithms. A mechanism to define a user-specified topology calculation methodology with a set of metric types and constraints for building other than shortest metric based topologies. This allows for an IGP to calculate the specific topology itself and not rely on the external TE component. Reading list: draft-ietf-lsr-flex-algo. - Topology scalability. A quarter of century ago ATM PNNI defined multilevel routing protocol loosely based on OSPF for addressing topology information overload problems, and that worked. Current developments for adjusting IGPs to operate well in large and densely interconnected meshes start to look into a similar direction by increasing the number of topology levels upward from two. Reading list: draft-li-hierarchical-isis, draft-li-area-abstraction. </tt> <tt>LSVR LSVR WG is a new working group focusing on development if a purpose-built routing protocol based on BGP components and targeted for a densely interconnected networks, with a particular focus to DC use cases. - Problem space. Definition of a problem to be solved and reasoning why a new routing protocol would be of value and need in the context of DC routing. Reading list: draft-ietf-lsvr-applicability. : - BGP SPF. The mechanics of operation of a proposed link state vector routing protocol. In essence, BGP transport intermixed with SPF topology calculation. Reading list: draft-ietf-lsvr-bgp-spf. </tt> <tt>MANET MANET WG focuses on developing of routing protocols for environments exhibiting many changes in topology and link availability. - DLEP extensions. Reading list: draft-ietf-manet-dlep-credit-flow-control, draft-ietf-manet-dlep-traffic-classification, draft-ietf-manet-dlep-multi-hop-extension, draft-ietf-manet-dlep-lid-extension. </tt> <tt>MPLS MPLS WG coordinates the development of MPLS dataplane encapsulation and control plane components required for its operation. Being an active WG for a third decade now, majority of core protocol work is complete, the focus is on maintenance and extensions required for adjacent uses of MPLS derivative technologies, and manageability. - MPLS modelling. Definition of YANG models for configuration and operation of MPLS functionality. Reading list: draft-ietf-mpls-base-yang, draft-ietf-mpls-static-yang. </tt> <tt>NVO3 NVO3 WG works on IP based encapsulations for network virtualization, with the focus on DC environments. - Geneve. VXLAN encapsulation, while not a product of an IETF WG, proved to be successful in the industry, reaching a wide universal deployment. As the requirements for encapsulation increased in order to fulfil different use cases, it became evident that VXLAN has fundamental limitations and a new encapsulation protocol is required. The work resulted in selecting Geneve as a successor to VXLAN, providing practical extensibility, hardware implementation efficiency, and security awareness. The work on Geneve is nearing completion. Reading list: draft-ietf-nvo3-encap, draft-ietf-nvo3-geneve. - EVPN control plane for NVO3. While NVO3 WG is not directly chartered to work on control plane components, practical deployments will be and are based on some form of control plane. EVPN is one possible candidate of such control plane, providing autodiscovery of participating NVEs and the distribution of addresses and their mappings. Reading list: draft-ietf-nvo3-evpn-applicability, draft-boutros-bess-evpn-geneve. - NVO3 security. An analysis of security requirements both for the NVO3 environment and NVO3 dataplane encapsulators. Reading list: draft-mglt-nvo3-geneve-security-requirements. </tt> <tt>PALS PALS WG works on maintenance of LDP signalled services that use pseudowires. - Ethernet PW CW. Mandating the use of control word for Ethernet pseudowires in order to avoid the possible aliasing problems based on inability to deterministically distinguish payload data from encapsulated frame header. Reading list: draft-ietf-pals-ethernet-cw. - Maintenance and extensions. The WG mostly focuses on extensions of existing signalling mechanisms and services, with nothing exceptional to report at this time. </tt> <tt>PCE PCE WG works on defining mechanisms for centralized topology computation for MPLS-derivative networks. - Applicability to Segment Routing. Reading list: draft-ietf-pce-segment-routing. - PCE modelling and manageability. Reading list: draft-ietf-pce-pcep-yang. </tt> <tt>PIM PIM WG works on development of IP multicast routing and signalling control plane components. - YANG models for IP multicast. Configuration and maintenance models for IP multicast control protocols and network element operation. Reading list: draft-ietf-pim-msdp-yang, draft-ietf-pim-igmp-mld-yang. - Protocol maintenance and extensions. One of the aspects related to PIM stability on multi-access networks is the proper election and maintenance of a DR. Trying to rely on the implicit expiration of DR timers and switching over only then does not necessarily lead to fast convergence, and does not allow for a deterministic selection of backup DR in advance. A proposed extension allows for carrying information about candidate DR nodes and makes a way for off-PIM liveness validation. Reading list: draft-ietf-pim-dr-improvement. </tt> <tt>RIFT RIFT WG works on a specialised routing protocol having a mixture of link-state and distance-vector operations, targeted for a specific Clos-based topologies that exhibit a large number of interconnections between points in the network. - Base specification. As for a relatively new WG, the current main focus is on base specification, including protocol mechanics and encodings, and targeted use cases. Reading list: draft-ietf-rift-rift, draft-filyurin-rift-access-networks. - Modelling. A configuration and operation YANG model for RIFT nodes. Reading list: draft-zhang-rift-yang. </tt> <tt>ROLL ROLL WG works on development of routing protocols for low power and lossy networks and nodes that have limited communication resources. - RPL applicability. A view on applicability of RPL routing protocol to low power and lossy networks. Reading list: draft-ietf-roll-rpl-observations. </tt> <tt>RTGWG RTGWG WG focuses on new and innovative topics related to routing that are either too wide for a specific existing subject WG at the time, or too narrow and not fitting any particular WG. It acts as an initial filter and redirection mechanism for new work coming into routing area. - BGP PIC. A set of mechanisms and recommendations on how a node can implement routing and forwarding logical data structures in order to limit the scope of changes needed to be done on the node related to the changes in routing topology, particularly targeting BGP environment. Reading list: draft-ietf-rtgwg-bgp-pic. - LNE and NI models. A set of YANG models describing the partitioning of a network element into instances or VRFs and how it can be represented as a hierarchy of manageable entities from the control plane component perspective. Reading list: - Routing policy modelling. A YANG model defining how a local network element routing policy (not the BGP routing policy) could be represented and used. Reading list: </tt> <tt>SFC SFC WG works on definition of an overall architecture and technology components for service chaining. - SFC OAM. A set of mechanisms for allowing to monitor and validate the operation of SFC environments. Reading list: draft-ietf-sfc-oam-framework. - SFC and In-situ OAM integration. Reading list: draft-ietf-sfc-ioam-nsh, draft-ietf-sfc-proof-of-transit. </tt> <tt>SPRING SPRING WG focuses on overall architectural development of Segment Routing and its associated protocols and mechanisms, as well as focusing on operational and usability aspects of it. - SR MPLS dataplane. The components and protocol mechanics for Segment Routing using MPLS dataplane. Reading list: draft-ietf-spring-segment-routing-mpls. - SR policy routing. A framework on how SR components could be bound together and used for implementation of a scalable source based routing mechanism. Reading list: draft-ietf-spring-segment-routing-policy. </tt> <tt>TEAS TEAS WG focuses on aspects related to traffic engineering technologies for MPLS and derivative dataplanes and signalling components. The core set of specifications has been completed, current work focuses on extensions and feature maintenance, and on development of YANG models. - TE topology modelling. Reading list: draft-ietf-teas-yang-te, draft-ietf-teas-yang-te-topo, draft-ietf-teas-te-topo-and-tunnel-modeling. - Enhanced VPN. A feasibility study on what IETF technology components could be reused and what needs to be developed for VPNs that would allow for stricter resource guarantees and awareness to network applications. Reading list: draft-dong-teas-enhanced-vpn. </tt> <tt>MBONED MBONED WG focuses on deployment and operation aspects of multicast technologies and networks. - YANG model for multicast configuration and monitoring. Reading list: draft-ietf-mboned-multicast-yang-model. - Multicast in DC environments. Multicast traffic especially in DC environments has been frowned upon for a long time, and the typical application communication pattern was predominantly point to point. Both of those assumptions start to change, and an analysis of what the effect of bringing in multicast at scale into DC environment would be needs to be performed. Reading list: draft-ietf-mboned-dc-deploy. - Multicast in wireless environments. IEEE 802 wireless is not the mostly friendly environment for IP multicast. Recommendations both for deployment, and for cross-SDO development of wireless and multicast technologies, are analysed. Reading list: draft-ietf-mboned-ieee802-mcast-problems. </tt> <tt>GROW GROW WG focuses on operational aspects of global BGP routing system and works on toolkits, methodologies, and protocols targeted for BGP operation and maintenance. - BMP maintenance. BMP is starting to get operational traction and thus limitations and shortcomings of the original design show up. The current work focuses on allowing BMP to be able to export information about local and outgoing RIBs, and a rather large item of work on extending the format and capabilities of Route Monitoring message. Reading list: draft-ietf-grow-bmp-adj-rib-out, draft-ietf-grow-bmp-local-rib, draft-hsmit-bmp-extensible-routemon-msgs. - Actions on Well-known communities. Different BGP implementations behave differently when setting or removing BGP standard communities, and this may result in inconsistent routing policy operation. The document provides the current list of vendor behaviour, and guidelines on what vendors should do for their implementations. Reading list: draft-ietf-grow-wkc-behavior. - RPKI AS Cones. A mechanism for aggregation of a list of client AS numbers for purposes of RPKI validation. Reading list: draft-ietf-grow-rpki-as-cones. </tt> <tt>SIDR SIDR WG has completed its chartered work and has been closed recently. The main deliverables of SIDR are BGPsec and RPKI. - BGPsec protocol specification. Reading list:RFC8205, RFC8206, RFC8207. - RTR maintenance. Reading list: RFC8210, RFC8211. </tt> <tt>SIDROPS SIDROPS WG focuses on deployment and operational aspects of global routing system security mechanisms by providing guidance on how protocols and mechanisms developed in SIDG WG couls and should be deployed and used, and acting as a distributor of operational knowledge. - TAL HTTPS transport. An extension allowing for use of HTTPS in addition to rsync for fetching trust anchors. Reading list: draft-ietf-sidrops-https-tal. - ASPA. AS Provider Authorization, a simple yet practical way of checking the validity of an AS path. Reading list: draft-azimov-sidrops-aspa-profile, draft-azimov-sidrops-aspa-verification. </tt> <tt>OPSAWG A WG for generic operations related topics that do not have any other more suitable or more specific WG. - TACACS. The documentation of the current deployed TACACS protocol, with the explicit goal of not defining new features and extensions but documenting the current state of the implemented and operated protocol. The specification carries more of a historical and informational value of what has been implemented. Reading list: draft-ietf-opsawg-tacacs. There is another document on defining YANG model for TACACS, it is an early start of the work and the scope is likely too narrow and too focused on TACACS only instead of having a broader scope of extending RFC7317 system authentication model to cover multiple authentication, authorization, and accounting mechanisms. Reading list: draft-zheng-opsawg-tacacs-yang. - IPFIX flow export based on BGP communities. Similar to NetFlow/IPFIX export of AS numbers and IP addresses, there may be use cases where a more granular and user-controlled marking of flows might be needed. The proposal defines a set of IPFIX information elements and a mechanism for exporting flows based on BGP communities of various types. Reading list: draft-ietf-opsawg-ipfix-bgp-community. - NAT modelling. A YANG model for configuration of various forms of NATs, providing a flexible framework for possible future additions of new NATs. Reading list: draft-ietf-opsawg-nat-yang. - Secure Device Install. A discussion in early stages on a simple proposal of zero-touch initial provisioning mechanism without requirement for remote hands intervention into network element configuration. With the cooperation of network element manufacturer, the initial configuration is encrypted with the public key of the node, thus locking the configuration to the intended target node and protecting it from the third parties that may be involved in the initial provisioning process. Reading list: draft-wkumari-opsawg-sdi. </tt> <tt>KARP KARP WG was focusing on transport security aspects of routing protocols, and has been closed a while ago due to the lack of energy. There seems to be a growing interest in the community on revisiting some of the work items of KARP, especially on developing a successor mechanism to TCP MD5 authentication signatures. - Routing transport security. TCP-AO has been around for a long time, however, there are no deployments as there are no practical implementations. Reading list: RFC5925. - Using IKE for routing protocols. This is a “homeless” document at this time, but worth reading and commenting on. The overall approach is quite simple – IKE is meant for distributing keying material, and if instead of IPsec components the users of that keying material would be routing protocols – could this work? It appears that it could, the overall solution is not that complex. Reading list: draft-mahesh-karp-rkmp. NETCONF NETCONF WG focuses on development of protocols components for evolving model based network management approaches. The core of both NETCONF and RESTCONF protocol work is complete, the focus is on extensions and adjustment to operational requirements as a feedback to deployments. - Event notifications and model based telemetry. Mechanisms for receiving events and data from network elements, as opposed to sending configuration and state into network elements. Reading list: draft-ietf-netconf-netconf-event-notifications, draft-ietf-netconf-yang-push. - Zero-touch provisioning. A set of mechanisms for initial bringup of network element.Reading list: draft-ietf-netconf-zerotouch. </tt> <tt> NETMOD NETMOD WG works on evolution of YANG modelling language and overall modelling methodology, as well as working on “core” set of models. - Datastore architecture. An architectural framework for allowing the configuration to be represented and interpreted in more than a single context, reflecting the operational reality of having the target configuration not necessary corresponding to the actual operating parameters. Reading list: RFC8342, draft-ietf-netmod-schema-mount. </tt> <tt>L2SM, L3SM L2SM and L3SM WGs were a short lived and narrow focused on developing the service model for L2VPN and L3VPN connectivity services – contrary to the work happening in BESS WG on element level configuration models for L2VPN and L3VPN. Reading list: RFC8049, RFC8466. </tt> <tt>IPPM IPPM WG works on measurement instrumentation – defining metrics, methodologies, and protocol extensions for measurement of IP network performance. - In-situ OAM. A set of mechanisms and encapsulation extensions that allow for recording of the measurements that are applicable to the transit packet within the packet itself. Reading list: draft-ietf-ippm-ioam-data , draft-brockners-ippm-ioam-geneve. - AURA. A multipath-aware measurement methodology and mechanisms. Reading list: draft-ietf-ippm-route. </tt> <tt>Other interesting assorted reading materials - FAST. An approach to coordination of and awareness to bidirectional routing. Reading list: draft-herbert-route-fast. - Protocol wire image. A methodology for analysing of visibility of protocol signatures and inferred working to a side observer. Reading list: draft-iab-wire-image. - Path signals. A set of analysis and recommendations on side effects of increasing use of encryption in packet networks. Reading list: draft-iab-path-signals. </tt> </body> </html>