RuggedCom RuggedServer RS401 - Manual (Page 3)

www.RuggedCom.com 3 RuggedSwitch™ RS401
RuggedServer™ RS401
4-Port Serial Device Server with Integrated 4-Port Managed Ethernet Switch
Serial IP Encapsulation
Many ‘legacy’ devices (RTU, PLC, IED, etc.) only support
serial communications via RS232 or RS485. ROS™
encapsulates the serial data within a TCP connection
allowing these devices to be reached via an IP network.
A wide range of baud rates, frame packetization options,
and diagnostics allows any serial protocol to function.
The RS401 has specific support for the following serial
protocols:
  „ Raw Socket serial encapsulation
  „ Modbus TCP (client and server)
  „ DNP 3
  „ WIN and TIN
  „ Microlok
MODBUS TCP
The Modbus protocol is ubiquitous in the industrial control
and automation world. ROS™ converts Modbus RTU
master/slave serial data packets to Modbus TCP client/
server packets for transmission over an IP network. This
allows communications to Modbus RTU slaves via Ethernet
and allows multiple masters to poll the same slave device.
Remote Dial-Up Access
A V.90 modem coupled with the PPP (Point to Point
Protocol) allows ROS™ to provide dial-up access via
POTS (plain old telephone system) providing connectivity
to serial devices and Ethernet LAN. PAP/CHAP
authentication provide security against unauthorized
access.
Enhanced Rapid Spanning Tree Protocol (eRSTP™)
RuggedCom eRSTP™ allows the creation of fault-
tolerant ring and mesh Ethernet networks that incorporate
redundant links that are ‘pruned’ to prevent loops.
eRSTP™ yields worst-case fault recovery1 of 5ms
times the ‘bridge diameter’ and allows rings of up to 160
switches. For example, a ring of ten switches will have fault
recovery times under 50ms. eRSTP™ implements both
STP and RSTP to ensure interoperability with commercial
switches unlike other proprietary ‘ring’ solutions.
Quality of Service (IEEE 802.1p)
Some networking applications such as real-time control or
VoIP (voice over IP) require predictable arrival times for
Ethernet frames. Switches can introduce latency in times of
heavy network traffic due to the internal queues that buffer
frames and than transmit on a first come first serve basis.
ROS™ supports ‘Class of Service’ in accordance with IEEE
802.1p that allows time critical traffic to jump ahead to the
front of the queue thus minimizing latency and reducing
jitter to allow such demanding applications to operate
correctly. ROS™ allows priority classification by port, tags,
MAC address, and IP type of service (TOS). A
configurable “weighted fair queuing” algorithm
controls how frames are emptied from the queues.
VLAN (IEEE 802.1Q)
Virtual local area networks (VLAN) allow the segregation
of a physical network into separate logical networks with
independent broadcast domains. A measure of security
is provided since hosts can only access other hosts on
the same VLAN and traffic storms are isolated. ROS™
supports 802.1Q tagged Ethernet frames and VLAN trunks.
Port based classification allows legacy devices to be
assigned to the correct VLAN.
IGMP Snooping
ROS™ uses IGMP snooping (Internet Group Management
Protocol v1&v2) to intelligently forward or filter multicast
traffic streams (e.g. MPEG video) to or from hosts on the
network. This reduces the load on network trunks and
prevents packets from being received on hosts that are not
involved. ROS™ has a very powerful implementation
of IGMP snooping that:
Can be enabled on a per VLAN basis  „
Detects and filters all multicast streams regardless of  „
whether subscribers exist
Supports “router-less” operation by supporting an  „
“active” mode
Restores traffic streams immediately after an RSTP  „
topology change
Ethernet Port Mirroring
ROS™ can be configured to duplicate all traffic on one port
to a designated mirror port. When combined with a network
analyzer, this can be a powerful troubleshooting tool.
Ethernet Port Configuration and Status
ROS™ allows individual ports to be ‘hard’ configured for
speed, duplex, auto-negotiation, flow control and more.
This allows proper connection with devices that do not
negotiate or have unusual settings. Detailed status of ports
with alarm and SNMP trap on link problems aid greatly in
system troubleshooting.
Ethernet Statistics and RMON
ROS™ provides continuously updating statistics per port
that provide both ingress and egress packet and byte
counters as well as detailed error figures. Also provided
is full support for the RMON statistics, history, alarms, and
event groups. RMON allows for very sophisticated data
collection, analysis and detection of traffic patterns.
Ethernet Switch Management Features