User`s guide

Filters
5-21
Figure 5-1. Using Filters To Restrict Access To An Adjoining Subnet
The company wishes to allow Engineering and Accounting
workstations to access resources on the FDDI backbone, but wants
to prevent Engineering users from accessing resources on the
Accounting subnet. Therefore, the objective is to set up a filter that
will block all traffic between LANs 3 and 4 while allowing users on
both LANs (3 and 4) to access LAN 2.
For simplicity sake, assume that LAN 3 and LAN 4 are connected
to the ATX's ports 3 and 4, respectively. LAN 2 is connected to the
ATX's port 2.
Two combination port filters are used to discard any packets from
Engineering destined for Accounting (LAN 3 to LAN 4) and any
POWER STATUS ENGINE STATUS TURBO STATUS SUPPLY A SUPPLY B 1.6 Gbps
RESET
PACKET PROCESSING ENGINE
NMS PORT
POWER
FastNET ATX
TM
OFFLINE
PROC
PWR
OCTAL IEEE 802.3 / ETHERNET 10BASE-T
3X 4X 5X 6X 7X 8X2X1X
SEGMENT
LINK
ACT
COL
12345678
OFFLINE
RING 1
RX ST
RING 2
RX ST
RING 3
RX ST
RING 4
RX ST PROC
TX 16 TX 16 TX 16 TX 16 PWR
QUAD IEEE 802.5 TOKEN RING (UTP)
OFFLINE
RX
LK
TX
QUAD FAST ETHERNET / 802.3 100BASE-FX
TX RX
SEGMENT 4SEGMENT 3SEGMENT 2 SEGMENT 1
RX
LK
TX
RX
LK
TX
RX
LK
TX
PROC
PWR
TX RX TX RX TX RX
OFFLINE
TX PWR
INTELLIGENT FDDI
RING A
RING B
THRU
WRAP RX
PROC
FDDI MIC A FDDI MIC BOPTICAL BYPASS
MULTI-MODE MULTI-MODE
OFFLINE
PROCRX
TX
PWR
QUAD IEEE 802.3 / ETHERNET 10BASE2
SEGMENT 4SEGMENT 3SEGMENT 2 SEGMENT 1
RX
TX
RX
TX
RX
TX
OFFLINE
PROCRX
TX
PWR
QUAD IEEE 802.3 / ETHERNET 10BASE2
SEGMENT 4SEGMENT 3SEGMENT 2 SEGMENT 1
RX
TX
RX
TX
RX
TX
Server Server
FDDI Backbone
LAN 12
Accounting subnet
LAN 14
Engineering subnet
LAN 13
ATX