End Station Tagging presentation 6/96   (960605e.txt 11:15am 96/96/05)


Slide 1:
End Station Tagging (Minding our p's and q's)
  Richard Hausman - Cisco
  Keith McCloghrie - Cisco
  Gideon Prat - Intel
  John Wakerly - Fore

Slide 2:
End-Station Tagging - Simple
  Powerfully flexible - "easy" VLANs by:
    MAC address  Application
    Protocol     User
  Appropriate end-station software layer can "do VLANs" at any layer
  Some types require only MAC driver upgrade
  Allows avoiding exceeding MTU

Slide 3:
Sophisticated vLAN Types
  {pretty picture showing different types of VLANs relating user,
  application network or link layers of multiple classic 7 layer
  station models; all using MAC layer tagging service}

Slide 4:
End-station software changes
  Applications using new APIs
  API extensions (e.g. Winsock 2)
  Protocol extensions to handle new API extensions
  API extensions (e.g. NDIS 4.0)
  MAC layer inserts tags

Slide 5:
End Station Tagging - could happen sooner than you think
  Minimal new infrastructure required in fabric
    Need little more than tag-aware forwarding / filtering
    May be possible without central vLAN membership control
    May be possible within a single spanning tree
  Can coexist with legacy traffic in switch fabric
    "Untagged" traffic is a distinct vLAN

Slide 6:
Roles of the Switches
  "Tag-aware" forwarding and filtering
  Policy based management control
    Balance end-station power with central control
      Insulation from too-powerful end-station ability to "configure"
       access to network resources
    Monitor network utilization and performance by VLAN
    Security

Slide 7:
Other Roles of the Switches
  Multiple spanning trees (per vLAN group?)
    Increase bandwidth - utilize parallel pathways for different vLANs
    Different pathways for different priorities?
  Tag/untag traffic for "legacy" end-stations
    Bring unmodified end-stations into the VLAN game
  Extend VLANs across LAN types

Slide 8:
802.1p Priority
  MAC address (station ID) - also serves as Priority Tag
  Tag inserted by end-station MAC layer
    Tag selected based on priority info
    Info is from protocols or application above
    Awkward for unicast addresses
  Same MAC layer tag requirement as for 802.1q tags, but
        different tagging mechanism

Slide 9:
Orthogonal Attributes
  VLAN membership and priority are both attributes suitable for
        end-station (or switch-initiated) tagging
  Can have priority without VLAN info
  Can have VLANs without priority info
  But VLAN and priority info could use the same insertion
        mechanism and tag

Slide 10:
Minding our p's and q's
  We can incorporate MAC level priority information in a 3-bit
        subfield of the (32-bit) vLAN tag
    3 bits provides the 8 levels drafted in .1p
    3 bits matches the 3 bits in 802.5 MAC headers
    Subfield could be in the Ethertype field, essentially
        using 8 "vLAN Ethertypes"
    Subfield could be in the vLAN ID field, reducing actual
        identifier to 13 bits

Slide 11:
Tags: 2 forms
  {pretty picture of field structure of priority in 802.1q tag - first
   form with 8 Ethertypes, distinguished by 3 low prder priority bits,
   second form with high order 3 of 16 VLAN ID bits used for priority}

Slide 12:
Ideas:
  Let Multicast standard (802.1p) fly without encumbrances
  Leverage .1q tags for multiple priorities per station (per
        single MAC address)
    This could be included in 802.1p or 802.1q
  Leverage end-station software for multimedia application services
        already in creation by IETF and others