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Use the commands in this chapter to configure and monitor SDLLC connections. For SDLLC parameter configuration information and examples, refer to the "Configuring SDLLC Media Translation" chapter in the Router Products Configuration Guide.
Use the sdllc partner interface configuration command to enable device-initiated connections for SDLLC. This command must be specified for the serial interface that links to the serial line device. Use the no form of this command to cancel the original instruction.
sdllc partner mac-address sdlc-address| mac-address | 48-bit MAC address of the Token Ring host |
| sdlc-address | SDLC address of the serial device that will communicate with the Token Ring host |
Disabled
Interface configuration
Both the MAC address of the Token Ring host and the SDLC serial line address are required to initiate connections with the Token Ring host.
The Token Ring host and the serial device communicate with each other through the router. Although the device is said to initiate connections, the router actually initiates connections with the Token Ring host on behalf of the serial device. As part of Cisco's SDLLC implementation, the serial device "thinks" that it is communicating with a host also on a serial line. It is actually the router that does all the frame and protocol conversions between serial and Token Ring devices.
There are two conditions under which a router will attempt to initiate a connection to a host on behalf of a serial device:
The router will continue trying once a minute to initiate a connection whenever one of these two conditions is met, until the host responds to its requests. When you no longer want the router to initiate connections with a host, use the no sdllc partner command.
In the following example, a serial device at SDLC address c2 wants to initiate a connection with a Token Ring host at MAC address 4000.0122.0001. The router initiates the connection on behalf of a serial device:
! sample global command
source-bridge ring-group 100
!
interface serial 0
! router initiates connections with Token Ring host at MAC address
! 4000.0122.0001 on behalf of serial device c2
sdllc partner 4000.0122.0001 c2
sdllc xid
Use the sdllc ring-largest-frame interface configuration command to indicate the largest I-frame size that can be sent to or received from the LLC2 primary station. Use the no form of this command to return to the default.
sdllc ring-largest-frame value| value | Frame size in bytes |
516 bytes
Interface configuration
Possible values for the value argument match those that are possible for the lf size of the various source-bridge remote-peer commands. You must ensure that your remote peer connection can support this largest frame size. Possible values for the value argument include 516, 1500, 2052, 4472, 8144, 11407, and 17800.
Faster screen updates to 3278-style terminals often can be obtained by allowing the Token Ring FEP to send as large a frame as possible and by allowing the router to segment the frame into multiple SDLC I-frames.
In the following example, the router can send or receive a frame as large as 11407 bytes from the LLC2 primary station. Any frames larger will be fragmented by the router:
! sample global command
source-bridge ring-group 100
!
interface serial 3
! largest frame sent or received on serial 3 is 11407 bytes
sdllc ring-largest-frame 11407
A dagger (+) indicates that the command is documented in another chapter.
source-bridge remote-peer fst +
source-bridge remote-peer interface +
source-bridge remote-peer tcp +
Use the sdllc sap interface configuration command to associate a service access point (SAP) value other than the default SAP value with a serial interface configured for SDLLC. Use the no form of this command to return this SAP value to its default state.
sdllc sap sdlc-address ssap dsap| sdlc-address | Virtual MAC address associated with the remote SDLC device. |
| ssap | Source SAP value. It must be in the range 1 through 254. |
| dsap | Destination SAP value. It must be in the range 1 through 254. |
4
Interface configuration
You use the sdllc sap command in conjunction with the sdllc traddr interface configuration commands. A SAP can be viewed as a port through which a higher-layer application can communicate with its counterpart (peer) operating on another system. While the standard SAP value for IBM SNA devices is 4, and NetBIOS devices is xF0, other values are allowed.
In the following example, source SAP and destination SAP values of 2 are specified for the remote SDLC device at the SDLC address C1 02 02:
interface Serial0
sdllc sap C1 02 02
sdllc traddr
Use the sdllc sdlc-largest-frame interface configuration command to indicate the largest information frame (I-frame) size that can be sent or received by the designated SDLC station. Use the no form of this command to return to the default value.
sdllc sdlc-largest-frame address value| address | Address of the SDLC station that will communicate with the Token Ring host |
| value | Largest frame size that can be sent or received by this SDLC station |
265 bytes
Interface configuration
Most SDLC devices are limited to frames of 265 bytes. I-frames received from the Token Ring station that are larger than this size will be properly fragmented.
In the following example, the router can send or receive a frame as large as 265 bytes (the default) from the SDLC station at address c6. Any frames larger will be fragmented by the router.
! sample global command
source-bridge ring-group 100
!
interface serial 4
! largest frame sent or received on serial 4 is 265 bytes
sdllc sdlc-largest-frame c6 265
Use the sdllc traddr interface configuration command to enable the use of SDLLC Media Translation on a serial interface. The address specified is a MAC address to be assigned to the serial station. Use the no form of this command to disable SDLLC Media Translation on the interface.
sdllc traddr xxxx.xxxx.xx00 lr bn tr| xxxx.xxxx.xx00 | MAC address to be assigned to the serial interface |
| lr | SDLLC virtual ring number |
| bn | SDLLC bridge number |
| tr | SDLLC target ring number |
Disabled
Interface configuration
Every control unit hooked off the serial line requires a virtual Token Ring MAC address (VTRA).This usually is assigned by the system administrator as a locally administered address (unique across the network).
When you enable SDLLC Media Translation by specifying the sdllc traddr command on a serial interface, you must specify a virtual Token Ring address (VTRA) for each serial station attached to the serial line. The last two hexadecimal digits. (that is, the last byte) of the VTRA must be 00. The router uses this byte to represent the SDLC address of a station on the serial link. That is, addresses in the range xxxx.xxxx.xx00 to xxxx.xxxx.xxFF are reserved for use by the router. It is very important that you adhere to this addressing requirement. If you do not, there may be a conflict between the VTRA and the addresses reserved by the router for the SDLC link.
The variables lr, bn, and tr represent the SDLLC virtual ring number, bridge number, and target ring number, respectively, that you assign to the interface. In design, the serial interface appears to be a ring, lr, on a source-route bridged network, and ties in through the bridge, bn, to the virtual ring-group, tr. This provides access to other, real rings through remote source-route bridging source-bridge remote-peer commands. Note that SDLLC can be configured on a router containing no Token Ring interface cards.
The sdllc traddr command automatically turns on the LLC2 process with default values. To change any of the LLC2 parameters, specify their values on the serial interface that is being enabled for SDLLC. This is done on the serial interface, even though LLC2 does not technically run on the serial interface, but on the SDLLC virtual ring associated with the serial interface. LLC2 commands can be configured after specifying the sdllc traddr command.
In the following example, SDLLC media translation is enabled off the serial 0 interface to a serial station at MAC address 0110.2222.3300. The SDLLC virtual ring number is 8, the bridge number is 1, and the target ring number is 100:
! global command to apply commands to the ring group
source-bridge ring-group 100
! remote peer at IP address 131.108.1.1 belongs to ring group 100 and uses
! tcp as the transport
source-bridge remote-peer 100 tcp 131.108.1.1
source-bridge remote-peer 100 tcp 131.108.2.2
!
interface serial 0
encapsulation sdlc-primary
! establish address of SDLC station off serial-0 as c1
sdlc address c1
! enable SDLLC media translation to serial station 0110.2222.3300
! on virtual ring 8, bridge 1, to target ring 100
sdllc traddr 0110.2222.3300 8 1 100
A dagger (+) indicates that the command is documented in another chapter.
sdllc sap
source-bridge remote-peer fst +
source-bridge remote-peer interface +
source-bridge remote-peer tcp +
Use the sdllc xid interface configuration command to specify an eXchanged ID (XID) value appropriate for the designated SDLC station associated with this serial interface. Use the no form of this command to disable XID processing for this address.
sdllc xid address xxxxxxxx| address | Address of the SDLC station associated with this interface. |
| xxxxxxxx | XID the router will use to respond to XID requests the router receives on the Token Ring (LLC2) side of the connection. This value must be 4 bytes (8 digits) in length and is specified with hexadecimal digits. |
Disabled
Interface configuration
XID requests and responses are usually exchanged before sessions are started. Be sure that the XID value configured on the router matches the IDBLK and IDNUM parameters configured on the host. The XID response to an XID request from the Token Ring host will contain the information you configured in the sdllc xid command. The host will check the XID response it receives with the IDBLK and IDNUM parameters (that are configured in the VTAM). If they match, the Token Ring host will initiate a session with the router. If they do not match, the host will not initiate a session with the router.
The following example specifies an XID value of 01720002 at address c2:
! sample global command
source-bridge ring-group 100
!
interface serial 0
! sdllc exchange identification value of 01720002 at address c2
sdllc xid c2 01720002
sdllc partner
Use the show interfaces privileged EXEC command to display the SDLC information for a given SDLC interface.
show interfacesThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show interfaces command for an SDLC primary interface supporting the SDLLC function:
router# show interfaces
Serial 0 is up, line protocol is up
Hardware is MCI Serial
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation SDLC-PRIMARY, loopback not set
Timers (msec): poll pause 100 fair poll 500. Poll limit 1
[T1 3000, N1 12016, N2 20, K 7] timer: 56608 Last polled device: none
SDLLC [ma: 0000.0C01.14--, ring: 7 bridge: 1, target ring: 10
largest token ring frame 2052]
SDLC addr C1 state is CONNECT
VS 6, VR 3, RCNT 0, Remote VR 6, Current retransmit count 0
Hold queue: 0/12 IFRAMEs 77/22 RNRs 0/0 SNRMs 1/0 DISCs 0/0
Poll: clear, Poll count: 0, chain: p: C1 n: C1
SDLLC [largest SDLC frame: 265, XID: disabled]
Last input 00:00:02, output 00:00:01, output hang never
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 517 bits/sec, 30 packets/sec
Five minute output rate 672 bits/sec, 20 packets/sec
357 packets input, 28382 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
926 packets output, 77274 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets, 0 restarts
2 carrier transitions
Table 25-1 shows the fields relevant to all SDLC connections.
| Field | Description |
|---|---|
| Timers (msec) | List of timers in milliseconds. |
| poll pause, fair poll, Poll limit | Current values of these timers, as described in the individual commands in this chapter. |
| T1, N1, N2, K | Current values for these variables, as described in the individual commands in this chapter. |
Table 25-2 shows other data given for each SDLC secondary configured to be attached to this interface.
| Field | Description |
|---|---|
| addr | Address of this secondary. |
| State | Current state of this connection. The possible values are:
|
|
VS | Sequence number of the next information frame this station sends. |
| VR | Sequence number of the next information frame from this secondary that this station expects to receive. |
| RCNT | Number of correctly sequenced I-frames received when the router was in a state in which it is acceptable to receive I-frames. |
| Remote VR | Last frame transmitted by this station that has been acknowledged by the other station. |
| Current retransmit count | Number of times the current I-frame or sequence of I-frames has been retransmitted. |
| Hold queue: | Number of frames in hold queue/Maximum size of hold queue. |
| IFRAMEs, RNRs, SNRMs,
DISCs | Sent/received count for these frames. |
| Poll: | "Set" if this router has a poll outstanding to the secondary; "clear" if it does not. |
| Poll count: | Number of polls, in a row, given to this secondary at this time. |
| chain: | Shows the previous (p) and next (n) secondary address on this interface in the round robin loop of polled devices. |
Use the show sdllc local-ack privileged EXEC command to display the current state of any current Local Acknowledgment connections, as well as any configured Passthrough Rings.
show sdllc local-ackThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show sdllc local-ack command:
router# show sdllc local-ack
local 1000.5a59.04f9, lsap 04, remote 4000.2222.4444, dsap 04
llc2 = 1798136, local act state = connected
Passthrough Rings: 4 7
In the display, the first two lines of the show sdllc local-ack command show that there is a Local Acknowledgment session between two Token Ring devices. The device on the local ring has a MAC address of 1000.5a59.04f9 with a SAP of 04. The remote device has a MAC address of 4000.2222.4444 with a SAP of 04. The state of the Local Acknowledgment session is connected.
The Passthrough Rings display is independent of the rest of the show sdllc local-ack command. The Passthrough Rings display indicates that there are two rings, 4 and 7, configured for Passthrough. This means that stations on these rings will not have their sessions locally acknowledged but will instead have their acknowledgments end-to-end.
Table 25-3 describes significant fields shown in the display.
| Field | Description |
|---|---|
| local | MAC address of the local Token Ring station with which the router has the LLC2 session. |
| lsap | Local SAP value of the Token Ring station with which the router has the LLC2 session. |
| remote | MAC address of the remote Token Ring station on whose behalf the router is providing acknowledgments. The remote Token Ring station is separated from the router via the TCP backbone. |
| dsap | Destination SAP value of the remote Token Ring station on whose behalf the router is providing acknowledgments. |
| llc2 | Pointer to an internal data structure used by technical support staff for debugging. |
| local-ack state: | The current state. Possible values are as follows:
|
|
Passthrough Rings | Ring number of the start ring and destination ring for the two IBM machines when you do not have Local Acknowledgment for LLC2 configured for your routers using RSRB. |
Use the source-bridge fst-peername global configuration command to set up a Fast Sequenced Transport (FST) peer name. Use the no form of this command to disable the IP address assignment.
source-bridge fst-peername local-interface-address| local-interface-address | IP address to assign to the local router |
Disabled
Global configuration
Using this command is the first step to configuring a remote source-route bridge to use FST.
The following example shows the use of the source-bridge fst-peername command:
source-bridge fst-peername 150.136.64.98
source-bridge remote-peer fst
Use the source-bridge remote-peer fst global configuration command to specify a Fast Sequenced Transport (FST) encapsulation connection. Use the no form of this command to disable the previous assignments.
source-bridge remote-peer ring-group fst ip-address [lf size] [version number]No FST encapsulation connection is specified.
Global configuration
The two peers using the serial-transport method will only function correctly if there are routers/bridges at the end of the serial line that have been configured to use the serial transport. The peers must also belong to the same ring group.
In the following example the source-bridge fst-peername command specifies an IP address of 150.136.64.98 for the local router. The source-bridge ring-group command assigns the router to a ring group. The source-bridge remote-peer fst command specifies ring group number 100 for the remote peer at IP address 150.136.64.97.
source-bridge fst-peername 150.136.64.98
source-bridge ring-group 100
source-bridge remote-peer 100 fst 150.136.64.97 version 2 RSRB
source-bridge
source-bridge fst-peername
source-bridge remote-peer interface
source-bridge remote-peer tcp
Use the source-bridge remote-peer interface global configuration command when specifying a point-to-point direct encapsulation connection. Use the no form of this command to disable previous interface assignments.
source-bridge remote-peer ring-group interface interface-name [mac-address] [lf size] no source-bridge remote-peer ring-group interface interface-nameNo point-to-point direct encapsulation connection is specified.
Global configuration
Use this command to identify the interface over which to send source-route bridged traffic to another router/bridge in the ring group. A serial interface does not require that you include a MAC-level address; all other types of interfaces do require MAC addresses.
It is possible to mix all types of transport methods within the same ring group.
The following example shows how to send source-route bridged traffic over interfaces serial0 and Ethernet0:
! send source-route bridged traffic over serial0
source-bridge remote-peer 5 interface serial0
! specify MAC address for source-route bridged traffic on Ethernet0
source-bridge remote-peer 5 interface Ethernet0 0000.0c00.1234
show interface
source-bridge
source-bridge remote-peer fst
source-bridge remote-peer tcp
Use the source-bridge remote-peer tcp global configuration command to identify the IP address of a peer in the ring group with which to exchange source-bridge traffic using TCP. Use the no form of this command to remove a remote peer for the specified ring group.
source-bridge remote-peer ring-group tcp ip-address [lf size] [local-ack] [priority] no source-bridge remote-peer ring-group tcp ip-addressNo IP address is identified.
Global configuration
If you configure one peer for LLC2 Local Acknowledgment, you need to configure both peers for LLC2 Local Acknowledgment. If only one peer is so configured, unpredictable (and undesirable) results will occur.
The two peers using the serial-transport method will only function correctly if there are routers/bridges at the end of the serial line that have been configured to use the serial transport. The peers must also belong to the same ring group.
In the following example, the remote peer with IP address 131.108.2.291 belongs to ring group 5. It also uses LLC2 Local Acknowledgment, priority, and RSRB protocol version 2:
! identify the ring group as 5
source-bridge ring-group 5
! remote peer at IP address 131.108.2.291 belongs to ring group 5, uses
! tcp as the transport, is set up for local acknowledgment, uses
! priority, and uses RSRB protocol form of this command 2
source-bridge remote-peer 5 tcp 131.108.2.291 local-ack priority form of this command 2
The following example shows how to locally administer and acknowledge LLC2 sessions destined for a specific remote peer:
! identify the ring group as 100
source-bridge ring-group 100
! remote peer at IP address 1.1.1.1 does not use local acknowledgment
source-bridge remote-peer 100 tcp 1.1.1.1
! remote peer at IP address 1.1.1.2 uses local acknowledgment
source-bridge remote-peer 100 tcp 1.1.1.2 local-ack
!
interface tokenring 0
source-bridge 1 1 100
Sessions between a device on Token Ring 0 that must go through remote peer 1.1.1.2 use Local Acknowledgment for LLC2, but sessions that go through remote peer 1.1.1.1 do not use Local Acknowledgment (that is, they "pass through").
source-bridge
source-bridge remote-peer fst
source-bridge remote-peer interface
Use the source-bridge ring-group global configuration command to define or remove a ring group from the router configuration. Use the no form of this command to cancel previous assignments.
source-bridge ring-group ring-group| ring-group | Ring group number. The valid range is 1 through 4095. |
No ring group is defined.
Global configuration
To configure a source-route bridge with more than two network interfaces, the ring-group concept is used. A ring group is a collection of Token Ring interfaces in one or more routers that are collectively treated as a virtual ring. The ring group is denoted by a ring number that must be unique for the network. The ring group's number is used just like a physical ring number, showing up in any route descriptors contained in packets being bridged.
To configure a specific interface as part of a ring group, its target ring number parameter is set to the ring group number specified in this command. You should not use the number 0, because it is reserved to represent the local ring.
In the following example, multiple Token Rings are source-route bridged to one another through a single router/bridge. These Token Rings are all part of ring group 7.
! all token rings attached to this bridge/router are part of ring group 7
source-bridge ring-group 7
!
interface tokenring 0
source-bridge 1000 1 7
!
interface tokenring 1
source-bridge 1001 1 7
!
interface tokenring 2
source-bridge 1002 1 7
!
interface tokenring 3
source-bridge 1003 1 7
source-bridge
Use the source-bridge sdllc-local-ack global configuration command to activate Local Acknowledgment for SDLLC sessions on a particular interface. Use the no form of this command to deactivate Local Acknowledgment for SDLLC sessions.
source-bridge sdllc-local-ackThis command has no keywords or arguments.
Disabled
Global configuration
This command must be issued only on the router with the serial interface(s). Once the command is issued, all SDLLC sessions between the two routers will be locally acknowledged. You cannot selectively choose which SDLLC sessions are to be locally acknowledged and which are not. Also, Local Acknowledgment is not supported when the LLC2 station is attached to Ethernet rather than to Token Ring.
The following example activates Local Acknowledgment for SDLLC sessions:
source-bridge ring-group 100
source-bridge remote-peer 100 tcp 131.108.1.1 local-ack
source-bridge remote-peer 100 tcp 131.108.2.2
source-bridge sdllc-local-ack
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