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LONWORKS Routers and Repeaters

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					LONWORKS Routers and Repeaters
The first table below compares the attributes of routers and repeaters. The second table
compares the attributes of different types of routers.

                                                         Router                            Physical Layer Repeater
Ethernet Analogy                        Router                                            Hub
OSI Layer                               3                                                 1
Transceiver Type                        Any                                               TP/FT-10, TP/LP-10
Maximum in series                       Virtually unlimited1                              1
Ports                                   2                                                 Unlimited (typ:  8)
Power Supply                            Yes                                               Yes (except linkpower)
Logical Installation                    Required                                          Not required
Typical delay (TP/FT-10)                3-4ms (not including queuing                      60 s (typ)
                                        for media access)
Local Buffering                         Yes                                               No
Transparent to collisions               No                                                Yes2
Transparent to noise                    No                                                No
Transparent to bad packets              No                                                Yes
Packet filtering                        Yes                                               No

                                           Repeater                 Bridge                 Learning              Configured
        Packet validation                 Yes                     Yes                     Yes                    Yes
        Packet filtering                  No                      Domain                  Domain,                Domain,
                                                                                          Subnet,                Subnet,
                                                                                          Group                  Group
        Transparent to                    Always                  Always                  Always, if no          Always, if no
        Service Pin                                                                       subnet given           subnet given
        Messages
        Configuration                     N/a                     N/a                     Automatic              By network
                                                                                          after each             management
                                                                                          reset                  tool
        Redundant                         No                      No                      No                     Possible
        configurations
        Same subnet on both               Possible3               Possible4               Not allowed            Not allowed
        sides

1
   The maximum number of routers in series is determined by the maximum transmit timer (3072ms) on one hand and the sum of
channel delays and router delays on the other. The maximum number of routers in a row is by far in excess of what a good design
should include, thus virtually unlimited.
2
   Due to propagation delays through the physical layer repeater, a collision might occur on one side of the PLR in isolation. The
corrupt packet, which results from the collision, appears on all ports, as the PLR is transparent to bad packets.
3 4
  , Prevents future changes to a different router type.

				
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posted:3/16/2010
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