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The Packet OC-3 Interface Processor (POSIP) is available on Cisco 7000 series routers with the 7000 Series Route Switch Processor (RSP7000) and 7000 Series Chassis Interface (RSP7000CI) and on Cisco 7500 series routers.
The POSIP is a fixed-configuration interface processor that uses second-generation Versatile Interface Processor (VIP2) technology. The POSIP provides a single 155.520-Mbps, OC-3 physical layer interface for packet-based traffic. This OC-3 interface is fully compatible with SONET and Synchronous Digital Hierarchy (SDH) network facilities and is compliant with RFC 1619, "PPP over SONET/SDH," and RFC 1662, "PPP in HDLC-like Framing." The Packet-Over-SONET specification is primarily concerned with the use of the PPP encapsulation over SONET/SDH links.
This feature is supported on these platforms:
For information on how to configure a POSIP interface, refer to the "Configure a Packet OC3 Interface" section in the "Configuring Interfaces" chapter in the Configuration Fundamentals Configuration Guide.
The commands listed in the "Configure a Packet OC3 Interface" section are the same except the command syntax changed from posi to pos for the following commands:
For information on other commands that can be used by the POSIP interface, refer to the Cisco IOS Release 11.2 configuration guides.
For examples of configuring a POSIP interface, refer to the "Packet OC-3 Interface Configuration Examples" section of the "Configuring Interface" chapter in the Configuration Fundamentals Configuration Guide.
This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 11.2 command references.
To clear the interface counters, use the clear counters EXEC command.
clear counters [type number]EXEC
This command first appeared in Cisco IOS Release 10.0.
This command was modified in Cisco IOS Release 11.2 P and 11.1 CA to change the posi keyword to pos.
This command clears all the current interface counters from the interface unless the optional arguments type and number are specified to clear only a specific interface type (serial, Ethernet, Token Ring, and so on).
| Keyword | Interface Type |
|---|---|
| async | Asynchronous interface |
| bri | Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) |
| dialer | Dialer interface |
| ethernet | Ethernet interface |
| fast-ethernet | Fast Ethernet interface |
| fddi | Fiber Distributed Data Interface (FDDI) |
| hssi | High-Speed Serial Interface (HSSI) |
| lex | LAN Extender interface |
| loopback | Loopback interface |
| null | Null interface |
| pos | Packet OC-3 interface |
| serial | Synchronous serial interface |
| tokenring | Token Ring interface |
| tunnel | Tunnel interface |
| vg-anylan | 100VG-AnyLAN port adapter |
The following example clears all interface counters:
clear counters
The following example clears the Packet OC-3 interface counters on a POSIP card in slot 1 on a Cisco 7500 series router:
clear counters pos 1/0
The following example clears interface counters on the serial interface residing on a Cisco 1000 series LAN Extender:
clear counters lex 0 serial
To reset the hardware logic on an interface, use the clear interface EXEC command.
clear interface type numberEXEC
This command first appeared in Cisco IOS Release 10.0.
This command was modified in Cisco IOS Release 11.2 P and 11.1 CA to change the keyword posi to pos.
Under normal circumstances, you do not need to clear the hardware logic on interfaces.
| Keyword | Interface Type |
|---|---|
| async | Async interface |
| atm | Asynchronous Transfer Mode (ATM) interface |
| bri | Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) |
| ethernet | Ethernet interface |
| fddi | Fiber Distributed Data Interface (FDDI) |
| hssi | High-Speed Serial Interface (HSSI) |
| loopback | Loopback interface |
| null | Null interface |
| pos | Packet OC-3 Interface Processor |
| serial | Synchronous serial interface |
| tokenring | Token Ring interface |
| tunnel | Tunnel interface |
| vg-anylan | 100VG-AnyLAN port adapter |
The following example resets the interface logic on HSSI interface 1:
clear interface hssi 1
The following example resets the interface logic on Packet OC-3 interface 0 on the POSIP in slot 1:
clear interface pos 1/0
The following example resets the interface logic on T1 0 on the CT3IP in slot 9:
clear interface serial 9/0/0:0
To specify the interface on a Packet OC-3 Interface Processor (POSIP) and enter interface configuration mode, use the interface pos global configuration command.
interface pos slot/port-adapter/port (on VIPs in Cisco 7000 series and Cisco 7500 series)| slot | Specifies the backplane slot number. On the Cisco 7000, the slot number can be 0, 1, 2, 3, or 4. On the Cisco 7010, the slot number can be 0, 1, or 2. The slots are numbered from left to right. On the Cisco 7505, the slot number can be 0, 1, 2, or 3 from bottom to top. On the Cisco 7507, the slot number can be 0 or 1 (CyBus0) and 4 through 6 (Cybus1), from left to right. On the Cisco 7513, the slot numbers are 0 through 5 (CyBus 0) and 8 through 12 (CyBus 1), from left to right. |
| port-adapter | On Cisco 7000 series and Cisco 7500 series routers, specifies the ports on a VIP card. The value must be 0. |
| port | Port number on the interface. The value must be 0. |
None
Global configuration
This command first appeared in Cisco IOS Release 11.2.
This command was modified in Cisco IOS Release 11.2 P and 11.1 CA to change the interface posi command to interface pos.
Each POSIP provides a single Packet OC-3 interface; as a consequence, the port number in this command is always 0.
The following example specifies the single Packet OC-3 interface on the POSIP in slot 2:
interface pos 2/0
pos framing-sdh
pos internal-clock
To select SDH STM-1 framing on a Packet OC-3 interface in Cisco 7000 series routers with the RSP7000 and RSP7000CI or in Cisco 7500 series routers, use the pos framing-sdh interface configuration command. To revert to the default SONET STS-3c framing, use the no form of this command.
pos framing-sdhThis command has no keywords or arguments.
SONET STS-3c framing
Interface configuration
This command first appeared in Cisco IOS Release 11.2.
This command was modified in Cisco IOS Release 11.2 P and 11.1 CA to change the posi framing-sdh command to pos framing-sdh.
In the following example, the interface is configured for SDH STM-1 framing:
interface pos 3/0 pos framing-sdh no shutdown
interface pos
pos internal-clock
To set the internal clock as the transmission clock source on a Packet OC-3 interface in Cisco 7000 series routers with the RSP7000 and RSP7000CI or in Cisco 7500 series routers, use the pos internal-clock interface configuration command. To revert to the default recovered receive clock as the transmission clock source, use the no form of this command.
pos internal-clockThis command has no keywords or arguments.
The recovered receive clock
Interface configuration
This command first appeared in Cisco IOS Release 11.2.
This command was modified in Cisco IOS Release 11.2 P and 11.1 CA to change the posi internal-clock command to pos internal-clock.
The following command reverts to the default recovered receive clock:
interface pos 3/0 no pos internal-clock
To enable SONET payload scrambling on a POS interface, use the pos scramble-atm interface command. To disable scrambling, use the no form of this command.
pos scramble-atmThis command has no keywords or arguments.
Scrambling is disabled
Interface configuration
This command was added in Cisco IOS Release 11.2 P and 11.1 CA.
SONET payload scrambling applies a self-synchronous scrambler (x^43+1) to the Synchronous Payload Envelope (SPE) of the interface to ensure sufficient bit transition density.
Both ends of the connection must use the same scrambling algorithm.
When enabling POS scrambling on a VIP2 POSIP on the Cisco 7500 series that has a hardware revision of 1.5 or higher, you can specify CRC 16 only (that is, CRC 32 is currently not supported). To determine the hardware revision of the POSIP, use the show diag command.
To determine whether scrambling is enabled on the interface, use the show interface pos command or show startup-config command.
The following example enables scrambling on the interface:
Router(config)#interface pos 3/0Router(config-if)#pos scramble-atmRouter(config-if)#no shutdownRouter(config-if)#endRouter#
interface pos
show interface pos
To display information about the Packet OC-3 interface in Cisco 7000 series routers with the RSP7000 and RSP7000CI or in Cisco 7500 series routers, use the show interfaces pos EXEC command.
show interfaces pos [slot/port-adapter/port] (on a VIP in Cisco 7000 series and Cisco 7500| slot | (Optional) On the Cisco 7000 series, specifies the backplane slot number. On the 7000, the slot number can be 0, 1, 2, 3, or 4. On the Cisco 7010, the slot number can be 0, 1, or 2. The slots are numbered from left to right. On the Cisco 7505, the slot number can be 0, 1, 2, or 3 from bottom to top. On the Cisco 7507, the slot number can be 0 or 1 (CyBus0) and 4 through 6 (Cybus1), from left to right. On the Cisco 7513, the slot numbers are 0 through 5 (CyBus 0) and 8 through 12 (CyBus 1), from left to right. |
| port-adapter | On the Cisco 7000 series and Cisco 7500 series, specifies the ports on a VIP. The value must be 0. |
| port | Port number on the interface. The value must be 0. |
EXEC
This command first appeared in Cisco IOS Release 11.2.
This command was modified in Cisco IOS Release 11.2 P and 11.1 CA to change the show interface posi command to show interface pos and to update the sample output.
The following is sample output from the show interfaces pos command on a Cisco 7513 router with one Packet OC-3 Interface Processor (POSIP):
Router# show interfaces pos 2/0/0
POS2/0/0 is up, line protocol is up
Hardware is cyBus Packet over Sonet
Description: PRI-T1 net to zippy (4K) to Pac-Bell
Internet address is 1.1.1.1/27
MTU 4470 bytes, BW 1000 Kbit, DLY 40000 usec, rely 255/255, load 1/255
Encapsulation HDLC, loopback not set, keepalive set (3 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:23:09
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
5 minute input rate 0 bits/sec, 1 packets/sec
5 minute output rate 1000 bits/sec, 1 packets/sec
1046 packets input, 54437 bytes, 0 no buffer
Received 485 broadcasts, 0 runts, 0 giants, 0 parity
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
4013 packets output, 1357412 bytes, 0 underruns
0 output errors, 0 applique, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
Table 51 describes significant fields in this output.
| Field | Description |
|---|---|
| POS2/0/0 is up, line protocol is up | Indicates whether the interface hardware is currently active and can transmit and receive or if it has been taken down by an administrator. |
| Hardware is cyBus Packet over Sonet | Hardware type. |
| Internet address is | Internet address and subnet mask. |
| MTU | Maximum transmission unit of the interface. |
| BW | Bandwidth of the interface in kilobits per second. |
| DLY | Delay of the interface in microseconds. |
| load | Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes. The calculation uses the value from the bandwidth interface configuration command. |
| Encapsulation | Encapsulation method assigned to interface. |
| loopback | Indicates whether loopbacks are set. |
| keepalive | Indicates whether keepalives are set. |
| Last input | Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed. |
| (Last) output | Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface. |
| Queueing strategy | First-in, first-out queuing strategy (other queueing strategies you might see are priority-list, custom-list, and weighted fair). |
| Output queue, drops input queue, drops | Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped because a queue was full. |
| 5 minute input rate 5 minute output rate | Average number of bits and packets received or transmitted per second in the last 5 minutes. |
| packets input | Total number of error-free packets received by the system. |
| bytes (input) | Total number of bytes, including data and MAC encapsulation, in the error-free packets received by the system. |
| no buffer | Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernets and bursts of noise on serial lines are often responsible for no input buffer events. |
| broadcasts | Total number of broadcast or multicast packets received by the interface. |
| runts | Number of packets that are discarded because they are smaller than the medium's minimum packet size. |
| giants | Number of packets that are discarded because they exceed the medium's maximum packet size. |
| parity | Report of the parity errors on the interface. |
| input errors | Total number of no buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so that this sum might not balance with the other counts. |
| CRC | Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data. On a serial link, CRCs usually indicate noise, gain hits or other transmission problems on the data link. |
| frame | Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems. |
| overrun | Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data. |
| ignored | Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. These buffers are different than the system buffers mentioned previously in the buffer description. Broadcast storms and bursts of noise can cause the ignored count to be incremented. |
| abort | Illegal sequence of one bits on the interface. |
| packets output | Total number of messages transmitted by the system. |
| bytes (output) | Total number of bytes, including data and MAC encapsulation, transmitted by the system. |
| underruns | Number of times that the far-end transmitter has been running faster than the near-end router's receiver can handle. |
| output errors | Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this might not balance with the sum of the enumerated output errors, as some datagrams can have more than one error, and others can have errors that do not fall into any of the specifically tabulated categories. |
| applique | Indicates an unrecoverable error has occurred on the POSIP applique. The system then invokes an interface reset. |
| interface resets | Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within a certain interval. If the system notices that the carrier detect line of an interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an unrecoverable interface processor error occurred, or when an interface is looped back or shut down. |
| carrier transitions | Number of times the carrier detect signal of the interface has changed state. |
For more information on POSIP, refer to Packet OC-3 Interface Processor (POSIP) Installation and Configuration publication.
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