B&B Electronics 7018TX - Manual - Manual (Page 18)

(Revised 8/3/2009) Page 18 of 138
Snooping is configured via the web console and if enabled, operates dynamically upon each power up.
Also, there can be manual only or manual and dynamic operation. Note that “static multicast group
address” can be used whether IGMP Snooping is enabled or not.
IGMP Snooping will function dynamically without user intervention. If some of the devices in the LAN do
not understand IGMP, then manual settings are provided to accommodate them. The Internet Group
Management Protocol (IGMP) is a protocol that provides a way for a computer to report its multicast group
membership to adjacent ‘routers’. In this case N-Tron 7018 series switches provide router-like
functionality. Multicasting allows one computer to send content to multiple other computers that have
identified themselves as interested in receiving the originating computer's content. Multicasting can be used
to transmit only to an audience that has joined (and not left) a multicast group membership. IGMP version 2
is formally described in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 2236.
IGMP version 1 is formally described in the Internet Engineering Task Force (IETF) Request for Comments
(RFC) 1112. The 7018 series supports v1 and v2.
N-Ring
N-Ring is enabled by default, and the switch is Plug and Play for N-Ring except that initially one must
enable an N-Ring enabled device to be the N-Ring Manager for a given N-Ring. Subsequently, N-Ring
operates dynamically upon each power up. Using N-Tron's proprietary N-Ring technology offers expanded
ring size capacity, detailed fault diagnostics, and a standard healing time of 30ms. The N-Ring Manager
periodically checks the health of the N-Ring via health check packets. If the N-Ring Manager stops
receiving the health check packets, it times out and converts the N-Ring to a backbone within 30ms. When
using all N-Ring enabled switches in the ring, a detailed ring map and fault location chart is also provided
on the N-Ring Manager’s web browser. N-Ring status is also sent from the N-Ring Manager to the N-View
OPC Server to identify the health status of the ring. Up to 250 N-Ring enabled switches can participate in
one N-Ring topology. Switches that do not have N-Ring capability may be used in an N-Ring, however the
ring map and fault location chart cannot be as detailed at these locations.
N-Link
The purpose of N-Link is to provide a way to redundantly couple an N-Ring topology to one or more other
topologies, usually other N-Ring topologies. Each N-Link configuration requires 4 switches: N-Link
Master, N-Link Slave, N-Link Primary Coupler, and N-Link Standby Coupler. N-Link will monitor the link
status of the Primary and Standby Coupler links. While the Primary Coupler link is healthy, it will forward
network traffic and the Standby Coupler link will block network traffic. When a problem is detected on the
Primary Coupler link, the Primary Coupler link will block network traffic and the Standby Coupler link will
forward network traffic. While the N-Link Master and Slave are in communication via the Control link,
only one Coupler link (Primary or Standby) will forward network traffic while the other Coupler link will
block network traffic.