Well Known Ethernet Multicast address

Ethernet frames with a value of 1 in the least-significant bit of the first octet[note 2] of the destination address are treated as multicast frames and are flooded to all points on the network. While frames with ones in all bits of the destination address (FF:FF:FF:FF:FF:FF) are sometimes referred to as broadcasts, Ethernet network equipment generally does not distinguish between multicast and broadcast frames. Modern Ethernet controllers filter received packets to reduce CPU load, by looking up the hash of a multicast destination address in a table, initialized by software, which controls whether a multicast packet is dropped or fully received.

  • Some well known Ethernet multicast addresses

    Ethernet multicast address Type Field Usage
    01:00:0C:CC:CC:CC 0x0802 CDP |(Cisco Discovery Protocol), VTP (VLAN Trunking Protocol)
    01:00:0C:CC:CC:CD 0x0802 Cisco Shared Spanning Tree Protocol Address
    01:80:C2:00:00:00 0x0802 Spanning Tree Protocol (for bridges) IEEE 802.1D
    01:80:C2:00:00:00, or 01:80:C2:00:00:03, or 01:80:C2:00:00:0E 0x88CC Link Layer Discovery Protocol
    01:80:C2:00:00:08 0x0802 Spanning Tree Protocol (for provider bridges) IEEE 802.1ad
    01:80:C2:00:00:01 0x8808 Ethernet flow control (Pause frame) IEEE 802.3x
    01:80:C2:00:00:02 0x8809 Ethernet OAM Protocol IEEE 802.3ah (A.K.A. “slow protocols”)
    01:80:C2:00:00:30 to 01:80:C2:00:00:3F 0x8902 Ethernet CFM Protocol IEEE 802.1ag
    01:00:5E:00:00:00 – 01:00:5E:7F:FF:FF 0x0800 IPv4 Multicast (RFC 1112), insert the low 23 Bits of the multicast IPv4 Address into the Ethernet Address (RFC 7042 2.1.1.)
    33:33:xx:xx:xx:xx 0x86DD IPv6 Multicast (RFC 2464), insert the low 32 Bits of the multicast IPv6 Address into the Ethernet Address (RFC 7042 2.3.1.)
    01:1B:19:00:00:00, or 01:80:C2:00:00:0E 0x88F7 Precision Time Protocol (PTP) version 2 over Ethernet (Layer-2)
  • source : https://en.wikipedia.org/wiki/Multicast_address

THREADGROUP

 

THREAD

THREAD.

Designed specifically for the home

Robust self-healing mesh network

No single point of failure

Interoperable by design using proven, open standards and IPv6 technology with 6LoWPAN as the foundation

Requires just a software enhancement for today’s 802.15.4 products

Neighbor Discovery

Neighbor Discovery Processes

  • Router discovery : Router Solicitation, Router Adverstisement
  • Prefix discovery : Distinguish onlink vs off link
  • Parameter discovery : additional operational parms
  • Address auto configuration : DHCP
  • Address resolution : Neighbor Solicitation, Neighbor Advertisement
  • Next-hop determination
  • Neighbor unreachability detection
  • Duplicate address detection
  • Redirect function : Better next hop

Neighbor Discovery Messages

  • Router Solicitation (133)
  • Router Advertisement (134)
  • Neighbor Solicitation (135)
  • Neighbor Advertisement (136)
  • Redirect (137)

All are accomplished by ICMP messages

Summary of ND Message and Options

  • Router Solicitation
    • Source Link-Layer Address
  • Router Advertisement
    • Source Link-Layer Address
    • Prefix Information
    • MTU
    • Advertisement Interval
    • Home Agent Information
    • Router Information
  • Neighbor Solicitation
    • Source Link-Layer Address
  • Neighbor Advertisement
    • Target Link-Layer Address
  • Redirect
    • Redirected Header
    • Target Link-Layer Address

Neighbor Discovery Processes

  • Address resolution (including duplicate address detection)
  • Router discovery (including prefix and parameter discovery)
  • Neighbor unreachability detection
  • Redirect function

Address Resolution Process

  • An exchange of NS and NA messages to resolve the link-layer address of the next-hop address
    • Multicast Neighbor Solicitation message
    • Unicast Neighbor Advertisement message
  • Both hosts update their neighbor caches
  • Unicast traffic can now be sent

Address Resolution Message

Host A – MAC: 00-10-5A-AA-20-A2 / IP : FE80::210:5AFF:FEAA:20A2

Host B – MAC: 00-60-97-02-6E-A5 / IP: FE80::260:97FF:FE02:6EA5

  1. Multicast Neighbor Solicitation
    Ethernet Header
        Destination MAC is 33-33-FF-02-6E-A5 (Ethernet Multicast Address)
    IPv6 Header
        Source Address is FE80::210:5AFF:FEAA:20A2
        Destination Address is FF02::1:FF02:6EA5 (Solited-node Address)
        Hop limit is 255
    Neighbor Solicitation Header
        Target Address is FE80::260:97FF:FE02:6EA5
    Neighbor Discovery Option
        Source Link-Layer Address is 00-10-5A-AA-20-A2
    
  2. Unicast Neighbor Advertisement
    Ethernet Header
        Destination MAC is 00-10-5A-AA-20-A2
    IPv6 Header
        Source Address is FE80::260:97FF:FE02:6EA5
    Destination Address is FE80::210:5AFF:FEAA:20A2
        Hop limit is 255
        Neighbor Solicitation Header
        Target Address is FE80::260:97FF:FE02:6EA5
    Neighbor Discovery Option
        Source Link-Layer Address is 00-60-97-02-6E-A5
    

Neighbor Unreachability Detection

  • A neighboring node is reachable if:
    • There has been a recent confirmation that IPv6 packets sent were received and processed by the neighboring node
  • Detects whether the first hop to the destination is reachable
  • Reachability is determined by:
    • Receipt of a Neighbor Advertisement message in response to a unicast Neighbor Solicitation message
    • Upper layer protocol indicators

Neighbor Unreachability States

Neighbor Unreachability States

from IPv6 Addressing (TechRef)

Duplicate Adddress Detection

Host A – Tentative IP: FEC0::2:260:8FF:FE52:F9D8

Host B – MAC: 00-60-08-52-F9-D8 / IP: FEC0::2:260:8FF:FE52:F9D8

  1. Multicast Neighbor Solicitation message
    Ethernet Header
        Dest MAC is 33-33-FF-52-F9-D8 (Ethernet Multicast Address)
    IPv6 Header
        Source Address is :: (Unspecified address)
        Destination Address is FF02::1:FF52:F9D8 (Solited-node Address)
        Hop limit is 255
    Neighbor Solicitation Header
        Target Address is FEC0::2:260:8FF:FE52:F9D8
    
  2. Multicast Neighbor Advertisement message
    Ethernet Header
        Destination MAC is 33-33-00-00-00-01 (Ethernet Multicast Address)
    IPv6 Header
        Source Address is FEC0::2:260:8FF:FE52:F9D8
        Destination Address is FF02::1 (All-nodes multicast address)
        Hop limit is 255
    Neighbor Advertisement Header
        Target Address is FEC0::2:260:8FF:FE52:F9D8
    Neighbor Discovery Option
        Target Link-Layer Address is 00-60-08-52-F9-D8
    

Router Discovery

  • Nodes discover the set of routers on the local link
  • IPv6 router discovery also provides:
    • Default value of Hop Limit field
    • Use of stateful address protocol
    • Reachability and retransmission timers
    • Network prefixes for the link
    • MTU of the local link
    • IPv6 mobility information
    • Routes

Router Discovery Message

Host A – MAC: 00-B0-D0-E9-41-43 / IP: none
Router – MAC: 00-10-FF-D6-58-C0 / IP: FE80::210:FFFF:FED6:58C0

  1. Multicast Router Solicitation Message
    Ethernet Header
        Destination MAC is 33-33-00-00-00-02 (Ethernet Multicast Address)
    IPv6 Header
        Source Address is :: (Unspecified address)
        Destination Address is FF02::2 (All node Multicast Address)
        Hop limit is 255
    Router Solicitation Header
    
  2. Multicast Router Advertisement Message
    Ethernet Header
        Destination MAC is 33-33-00-00-00-01 (Ethernet Multicast Address)
    IPv6 Header
        Source Address is FE80::210:FFFF:FED6:58C0
        Destination Address is FF02::1 (All node Multicast Address)
        Hop limit is 255
    Router Advertisement Header
        Current Hop Limit, Flags, 
        Router Lifetime, 
        Reachable and Retransmission Timers
    Neighbor Discovery Options
        Source Link-Layer Address is 00-10-FF-D6-58-C0
        MTU is 1500
        Prefix Information is for FEC0:0:0:F282::/64 
    

Ref.

1. Neighbor Discovery

2. TCP/IP Fundamentals for microsoft windows

3. IPv6 Addressing

4. IPv6 Neighbor Discovery