Tools and technologies

        IPv6
        SONET and ATM
        H.320 and H.323
        RSVP and Diffserv
        Gigapops
        New protocols and security
        Universities
SONET
        lock-based framing based on special flag sequence but without
escape mechanism
        encoding standard
        multiplexes slower speeds exceptionally well
        frames are 125 usec regardless of speed
H.322 and H.323
        H.322 Visual Telephone Terminals over Guaranteed QOS LANs

simple extension of H.320 circuit switched (narrow-band video - codecs over Px 64 kbps
may have unreliable service options

H.323 Visual Telephone Terminals over Non- Guaranteed QOS LANs -video over IP
H.323 Design Goals

        Interwork with a wide variety of terminal devices and networks
        Operate at asymmetric video bit rate, frame rates, and resolutions
        Must support lower layer coding and resolution standards
        Uses H.245 for control and information exchange
        Gatekeeper provides address translation, controls access and manage

bandwidth and gateway identification
H.323 v1 ------> v2

        Explicit Gateway behavior (H.246)
        Security (H.235)
        Large loosely coupled conferences added to basic tight control
conferencing
        Alternative media transports (ATM)
        Extended Gatekeeper functionality
        QoS reservation

H.323 Architecture
H.323 Standard
H.323 Components

        Terminal
        Gatekeeper
        Gateway
        MCU
Gatekeeper
        Call admission/authorization
        Centralized point for resource reservation
        Address translation and/or redirection (interacts with endpoints)
        Optional traffic cop for terminals, gateways, MCU by controlling

bandwidth used
Gateway

        Provides interoperability between different telecommunications systems
        Gateways within each domain negotiate encodings, protocols and
control mappings
        H.323 Proxies are special null gateways between two H.323 systems

to handle firewalls and addressing
Service Classes

        guaranteed
        predictive - soft guarantees
        controlled-delay - cuts the tail on the delay curve; enables
playback buffers
        best-effort
QOS and RSVP
        flowspecs - shapes the request
        admission control - determines if request can be met
        resource reservation / signalling - reserving network resources
        packet scheduling in routers and switches
Flowspecs
        Rspec - service requested from net, eg. delay of n ms, predictive
of bw n kbps
        Tspec- application negotiation with network characteristics

token bucket approach: token rate r and Bucket depth B shapes a long-term rate and a short-term characteristic

                allows same average but different needs
                likely an iterative, interactive process
Admission Control
        based upon the Tspec and Rspec, and the current state of the
network, accept or refuse the request
        very dependent on router technologies and service requested
        not policing to see if the flow is following its requested specs
RSVP
        soft-state, to reflect the real Internet
        supports multicast very efficiently
        receiver-oriented - receivers keep track of their needs, not the sender
        separate from route establishment
        reserves router resources, not line bandwidth
The problems with RSVP
        mapping onto ATM
        scaling
        authentication
        Receiver generates reservation
Diff-serv
        premium service via TOS field
        scalable but only offers soft guarantees
        bandwidth brokers and user profiles
        uncertainty on how to use the header bits
        interactions with IPSec and other new techs
        what happens behind the bandwidth broker?
Packet scheduling
        Associate each packet with its appropriate flow
                source and dest ip address
                source and dest tcp port
        provide queue managers with a service class
        how many classes can a router handle?
Queue manager
        Manage the packets in the queues so that they receive the requested
circuit
        FIFO   - Fair queuing  - Weighted fair queuing
Real Time Protocols
        streaming
        RTP - built on UDP, offers no guarantees of real-time performance,
payload handler per media stream for association and synch
        RTCP - statistics and control
Gigapops
        High-speed exchange points for I2 and I1
        Measurement and policy control
        Can be centralized or distributed
        Will house outboard servers
        A routing thrill
Classes of Service
        by application
                allow certain applications to access high-speed devices
        by desktop
                highbandwidth to the desktop
                multiple parallel campus backbones
                WAN PVC's
                by IP address (and user)
Security
        interrealm authentication
        authorization
        Kerberos
        X.509 and a PKI or SPKI
Universities
        Due to their teaching mission, universities scatter researchers
        University faculty and students therefore have a disproportionate
need to be able to collaborate at a distance
        Source of invention
        Support of guinea pig populations
        Training of the next-generation of consumers and workers
        Evaluation and assessment of societal impacts
Key Issues
        How many bearer services
        Middleware
        Network management and routing tools
        How to do QOS