This chapter describes the steps necessary to install the cabling that enables The MESH control network equipment to communicate.
Installation of The MESH control network consists of locating the individual components and then making connections between them using fiber optic or copper cable. The following para-graphs provide the information necessary for the cabling installation of the high performance sys-tem network.
NOTE
Refer to the documentation included with your Invensys qualified Ethernet switches to install these switches and the media converters as part of The MESH control network.
Connecting The MESH Control Network Components
Fiber Optic Cabling Guidelines
The following guidelines should be followed when making fiber optic connections between devices in The MESH control network:
♦ Minimum bend radius - Fiber optic cable can be damaged if it is bent too sharply.
Maintain a minimum bend radius of two inches when using fiber optic cable supplied by Invensys. Follow the cable manufacturers guidelines if third-party fiber optic cable is used.
♦ Cable straps - Cable straps, if used, should be designed for use with fiber optic cable.
Hard plastic cable ties can damage fiber optic cable and are not recommended.
♦ Dust caps - Dust caps should remain in place to protect the polished cable ends over the cable ends and in the switches while cables are being routed. Dust caps should be installed on unused switch ports and device ports.
Interconnecting Ethernet Switches
Depending on which switch model has been selected as the root network switch, additional switches may be connected in one of several ways. They are summarized in Table 3-1 below. Refer to the “Ethernet Switch Interconnection Diagrams” in the documentation included with your Invensys qualified Ethernet switches for detailed cabling diagrams.
B0700AZ – Rev L 3. Installation (Cabling)
CAUTION
!
If Fast Ethernet “Device” ports are used as uplink ports between switches on an N-Series chassis switch configuration, it is very important that the switch spanning tree protocol settings be configured correctly. Failure to do so will cause system deg-radation during switch failover, causing excessive packet flooding possibly resulting in device failures. (Refer to The MESH Control Network Operation, and Switch Instal- lation and Configuration Guide (B0700CA).)
CAUTION
!
Do not make direct interconnection between ports of the same switch (i.e. loop-back). Loopbacks can result in network failures upon a loss or failure of RSTP.
Also, refer to page 61 for a list of single mode fiber optic cables for use at patch panels.
NOTE
All graphics of switches and media converters below are intended as generic illustra-tions of networking concepts and do not necessarily reflect the currently offered products.
NOTE
These sections pertain to both standard switches and chassis switches.
Uplink Port to Uplink Port
The Ethernet switches can be connected to each other through the use of an optional uplink port.
Depending upon which uplink module is installed, the switch is able to communicate over single mode or multimode fiber optic cable, or CAT5 copper cable. Transmission via uplink ports is made using the Gigabit Ethernet protocol. The fiber optic cable uses LC type connectors and should be designed for the mode (single mode vs. multimode) of uplink module that is installed in the Ethernet switch’s interface slot. Figure 3-1 shows a connection between two Ethernet
Table 3-1. Methods of Connecting Ethernet Switches
Root Switch Port End Switch Port
Uplink port (Gigabit Ethernet) copper and fiber
Uplink port (Gigabit Ethernet) Fiber optic port (100Base-FX) Fiber optic port (100Base-FX) Fiber optic port (100Base-FX) RJ-45 (100Base-TX)
RJ-45 (10Base-T/100Base-TX) RJ-45 (10Base-T/100Base-TX) RJ-45 (10Base-T/100Base-TX) Fiber optic port (100Base-FX)
Figure 3-1. Switch-to-Switch Fiber via Uplink Port
Managed switches can be connected directly to other switches connecting each switch’s fiber optic ports with fiber optic cable.
NOTE
Make sure that the transmit (TX) port of one switch is connected to the receive (RX) port of the other switch. The standard Invensys LC to LC cable ensures proper TX to RX connections.
Fiber optic cable can be used to connect fiber switches to other fiber switches using each device’s 100Base-FX fiber ports. Multimode fiber cable with MT-RJ connectors is connected between a port on each switch. Figure 3-2 gives an example of a port-to-port connection via fiber optic cable. However, even though this method can be used for uplink ports it is not recommended due to the 100 Mb port's bandwidth capabilities. This method of uplinks must not be used for the Security Enhanced Configuration topology designs. Normally 1 Gb uplink connections should be used to interconnect switches in all standard or enhanced network designs.
Figure 3-2. Port-to-Port Connection via Fiber Optic Ports Fiber Switch
62.5/125 micron Single/Multimode w/LC-type Connectors
Fiber Optic Cable
1000Base-SX, 1000Base-LX or 1000Base-ZX Fiber Switch
Fiber Switch Fiber Switch
62.5/125 micron Multimode w/LC Connectors
Fiber Optic Cable 100Base-FX
B0700AZ – Rev L 3. Installation (Cabling)
CAUTION
!
If Fast Ethernet “Device” ports are used as uplink ports between switches, it is very important that the switch spanning tree edge-port protocol settings be configured correctly. Failure to do so will cause system degradation during switch failover, caus-ing excessive packet floodcaus-ing possibly resultcaus-ing in device failures. (Refer toThe MESH Control Network Operation, and Switch Installation and Configuration Guide (B0700CA).)
RJ-45 Port to RJ-45 Port
Switches can be connected to other switches through an RJ-45 port on each switch. It is necessary that the first switch’s transmit signal is connected to the second switch’s receive line. The same is true for the second switch’s transmit and receive signals. However, even though this method can be used for uplink ports it is not recommended due to the 100 Mb port's bandwidth capabilities and the RJ-45 auto-negotiation characteristics. This method of uplinks is not recommended for the enhanced network topology designs. Normally 1 Gb uplink connections should be used to interconnect switches in all standard or enhanced network designs. Figure 3-3 shows a connection between a copper switches with auto MDI/MDI-X ports.
Figure 3-3. Connecting Switches via RJ-45 Ports
In the event that neither switch has an MDI/MDIX port, a separate crossover cable (P0971PK - with a 1 ft cable), called a null hub, must be used between the switches.
Switch Configuration
Refer toThe MESH Control Network Operation, and Switch Installation and Configuration Guide (B0700CA) and the documentation included with your Invensys qualified Ethernet switches for instructions on configuring them for The MESH control network.
Copper Switch
100Base-TX
Auto
MDI/MDI-X Auto
MDI/MDI-X Copper Switch