Allied Telesis 86241-06 manual Bit Parity Mode

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Patch 86241-06 For Rapier Switches

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into 8 blocks of 85 bits with 84 bits available for payload, and one bit for framing overhead. The frame structure is shown in Figure 1 on page 23.

Figure 1: DS3 Framing Structure.

M-Frame 4760 bits

X1 679 X2

Bits

679	P1	679	P2	679	M1	679	M2	679	M3	679
Bits		Bits		Bits		Bits		Bits		Bits

First M-Subframe 680 bits

X1 84 INFO

F1 84 INFO

C1 84 INFO

F2 84 INFO

C2 84 INFO

F3 84 INFO

C3 84 INFO

F4 84 INFO

DS31

The switch with the DS3 interface is called the near end. The entity the switch connects to is called the far end. X1 and X2 are set to 1 if the near end is receiving an Alarm Indication Signal (AIS), a Loss Of Frame (LOF), or a Loss Of Signal (LOS). This allows the near end to indicate to the far end that it is experiencing a problem and is known as Far End Receive Failure (FERF).

P1 and P2 form the P-bit channel. They provide parity information for the preceding M-frame.

M1, M2, and M3 form a frame alignment channel used by the hardware to locate all seven M-subframes.

F1, F2, F3, and F4 form an M-subframe alignment channel which is used by the hardware to identify all frame overhead bit positions.

C1, C2, and C3 form the C-bit channel.

C-bit Parity Mode

In C-bit parity mode the C-bits are described as follows:

■The first C-bit in M-subframe 1 is set to 1 to identify the format as C-bit parity. If this is zero the format is assumed to be M23.

■The second C-bit in M-subframe 1 is designated Nr and is set to 1.

■The third C-bit in M-subframe 1 provides the Far End Alarm and Control signal (FEAC) which is used to:

•Send alarm or status information from the far end back to the near end.

•Initiate DS3 loopbacks.

The three C-bits in M-subframe 3 are designated as CP-bits and are used to implement CP-bit parity. At the near end the CP-bits are set to the same value as the P-bits. The parity of the CP-bits of frame N are compared with the parity of the CP-bits of frame N+1. A difference in parity between N and N+1 is deemed a CP-bit parity error.

Patch 86241-05 for Software Release 2.4.1 C613-10340-00 REV E

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Contents Patch For Rapier Switches PCR Module BGP Level PCR Module IPG LevelPCR Module SWI PCR Module PIM LevelPCR Module Utility Level PCR Module SSH LevelPCR 03064 Module Snmp Level PCR Module SWI LevelPCR 03113 Module Dvmrp Level PCR 03100 Module Dhcp LevelPCR Module FR, PPP Level PCR 03108 Module Mlds LevelPCR Module Ospf Level PCR 03123 Module Dhcp LevelPCR Module DS3 Level PCR Module IPV6 LevelPCR Module IPG, SWI, Vlan Network affecting No PCR 02315 Module Snmp Network affecting NoPCR Module DS3 Network affecting No PCR Module IPv6, SWI, IPG, Vlan Network affecting NoPCR Module Firewall Network affecting No PCR Module Install Network affecting NoPCR Module User Network affecting No PCR Module Utility Network affecting NoPCR Module Ping Network affecting No PCR Module IPG Network affecting NoPCR Module Network affecting No PCR Module Ospf IPG Network affecting NoPCR 02532 Module FIREWALLNetwork affecting No PCR 02523 Module QOS, Utility Network affecting NoPCR Module TELNET, PING, IPV6, Network affecting No PCR 02529 Module FIREWALLNetwork affecting NoPCR Module SWI Network affecting No PCR 02538 Module Dvmrp Network affecting NoPCR Module Classifier Network affecting No PCR Module IPV6 Network affecting NoPCR 02467 Module Core Network affecting No PCR 02574 Module DVMRPNetwork affecting NoPCR 02579 Module FIREWALLNetwork affecting No PCR 02587 Module OSPFNetwork affecting NoPCR 02498 Module Vlan Network affecting No PCR 02469 Module TMNetwork affecting NoPCR Module IPG, PIM, SWI Network affecting No PCR 02495 Module Vlan Network affecting NoPCR Module Vrrp Network affecting No PCR 02502 Module Ping, IPv6Network affecting NoPCR 02509 Module DVMRPNetwork affecting No PCR Module DNS Relay Network affecting NoPCR Module TELNET, TTY Network affecting No PCR Module BGP Network affecting NoPCR Module Tpad Network affecting No PCR 02277 Module Dvmrp Network affecting NoPCR 02301 Module IPGNetwork affecting No PCR 02303 Module INSTALLNetwork affecting NoPCR 02292 Module IPSECNetwork affecting No PCR 02294 Module IKMPNetwork affecting NoPCR Module Ipsec Network affecting No PCR Module FR Network affecting NoPCR Module IPG/FIREWALL Network affecting No PCR Module IPG, ETH Network affecting NoPCR Module SCC, SYN, PPP Network affecting No PCR Module PPP Network affecting NoPCR Module BGP, IPG Network affecting No PCR 02348 Module Enco Network affecting NoPCR 02397 Module Dvmrp Network affecting No PCR Module FFS, FILE, TTY Network affecting NoPCR Module VRRP, TRG Network affecting No PCR Module IPG Network affecting No Module Vrrp PCR Module Trace Network affecting NoPCR Module SNMP, CORE, SHOW, Network affecting No PCR Module STP Network affecting NoPCR 02463 Module DVMRP, IPG Network affecting No PCR 02450 Module IPV6Network affecting NoPCR 02452 Module IPv6Network affecting No PCR 02457 Module IPV6Network affecting NoPCR Module Switch Network affecting No PCR Module DHCP, IPG Network affecting No DS3 InterfacesBit Parity Mode Loopbacks DS3 Configuration Patch Release Note Disable DS3 Debug Disable DS3 Test Enable DS3 Debug Create Framerelay Show Framerelay Dynamic Port Security Availability