Table Of Contents

STUN and BSTUN Commands

bsc char-set

bsc contention

bsc fdx

bsc pause

bsc poll-timeout

bsc primary

bsc retries

bsc secondary

bsc servlim

bsc spec-poll

bstun group

bstun keepalive-count

bstun peer-name

bstun protocol-group

bstun remote-peer-keepalive

bstun route

encapsulation bstun

encapsulation stun

locaddr-priority-list

priority-group

priority-list protocol bstun

priority-list protocol ip tcp

priority-list stun address

queue-list protocol bstun

queue-list protocol ip tcp

sdlc virtual-multidrop

show bsc

show bstun

show stun

stun group

stun keepalive-count

stun peer-name

stun protocol-group

stun quick-response

stun remote-peer-keepalive

stun route address interface dlci

stun route address interface serial

stun route address tcp

stun route all interface serial

stun route all tcp

stun schema offset length format

stun sdlc-role primary

stun sdlc-role secondary

STUN and BSTUN Commands

---

Cisco's serial tunnel (STUN) feature allows Synchronous Data Link Control (SDLC) or High-Level Data-Link Control (HDLC) devices to connect to one another through a multiprotocol internetwork rather than through a direct serial link. STUN encapsulates SDLC frames in either the Transmission Control Protocol/Internet Protocol (TCP/IP) or the HDLC protocol. STUN provides a straight passthrough of all SDLC traffic (including control frames, such as Receiver Ready) end-to-end between Systems Network Architecture (SNA) devices.

Cisco's SDLC Local Acknowledgment provides local termination of the SDLC session, so that control frames no longer travel the WAN backbone networks. This means end nodes do not time out, and a loss of sessions does not occur. You can configure your network with STUN, or with STUN and SDLC Local Acknowledgment. To enable SDLC Local Acknowledgment, routers must first be enabled for STUN and configured to appear on the network as primary or secondary SDLC nodes. TCP/IP encapsulation must be enabled. Cisco's SDLC Transport feature also provides priority queuing for TCP encapsulated frames.

Cisco's block serial tunnel (BSTUN) implementation enables Cisco series 2500, 4000, and 4500 routers to support devices that use the Binary Synchronous Communication (BSC) data link protocol This enables enterprises to transport BSC traffic and SNA multiprotocol traffic over the same network.

Use the commands in this chapter to configure BSTUN, BSC, STUN, and SDLC Local Acknowledgment networks. For STUN and BSTUN configuration information and examples, refer to the "Configuring STUN and BSTUN" chapter in the Router Products Configuration Guide.

bsc char-set

Use the bsc char-set interface configuration command to specify the character set used by the BSC support feature in this serial interface as either EBCDIC or ASCII.

bsc char-set char-set
no bsc char-set char-set

Syntax Description

char-set

The character set. Valid keywords are ebcdic or ascii.

Default

EBCDIC is the default character set.

Command Mode

Interface configuration

Example

The following command specifies that the ASCII character set will be used:

bsc char-set ascii

bsc contention

Use the bsc contention interface configuration command to specify that the BSC link connected to the serial interface is a point-to-point BSC station. Use the no form of this command to cancel the specification.

bsc contention
no bsc contention

Syntax Description

This command has no arguments or keywords.

Default

BSC contention is disabled by default.

Command Mode

Interface configuration

Usage Guidelines

Because there is no address field used in the point-to-point BSC, a dummy address 01H is always used for encapsulation. To remove this address dependency, use the bstun route all command for point-to-point BSC link.

Example

The following command specifies that the BSC link connected to the serial interface is a point-to-point BSC station:

bsc contention

Related Command

bstun route

bsc fdx

The full-duplex interface configuration command replaces the bsc fdx command. Refer to the description of the full-duplex command in the "Interface Commands" chapter of this document for information on how to specify full-duplex mode.

bsc pause

Use the bsc pause interface configuration command to specify the interval to the tenth of a second, between the start of a polling cycle. Use the no form of this command to cancel the specification.

bsc pause time
no bsc pause time

Syntax Description

time	Interval in tenths of a second.

Default

The default interval is 1 second.

Command Mode

Interface configuration

Example

The following command sets the interval to 2 seconds:

bsc pause 20

bsc poll-timeout

Use the bsc poll-timeout interface configuration command to specify the polling timeout to the tenth of a second. Use the no form of this command to cancel the specification.

bsc poll-timeout time
no bsc poll-timeout time

Syntax Description

time	Time in tenths of a second.

Default

The default poll timeout is 1 second.

Command Mode

Interface configuration

Example

The following command sets the interval to 2 seconds:

bsc poll-timeout 20

bsc primary

Use the bsc primary interface configuration command to specify that the router is acting as the primary end of the BSC link connected to the serial interface, and that the attached remote devices are BSC tributary stations. Use the no form of this command to cancel the specification.

bsc primary
no bsc primary

Syntax Description

This command has no arguments or keywords.

Default

No default is specified.

Command Mode

Interface configuration

Usage Guidelines

The BSC support feature in the serial interface uses the address of the incoming encapsulation for reply.

Example

The following example specifies the router as the primary role:

bsc primary

Related Command

bstun route

bsc retries

Use the bsc retries interface configuration command to specify the number of retries performed before a device is considered to have failed. Use the no form of this command to cancel the specification.

bsc retries retries
no bsc retries retries

Syntax Description

retries

Number of retries before a device fails.

Default

The default number of retries is 5.

Command Mode

Interface configuration

Example

The following command sets the retry count to 10:

bsc retries 10

bsc secondary

Use the bsc secondary interface configuration command to specify that the router is acting as the secondary end of the BSC link connected to the serial interface, and the attached remote device is a BSC control station.

bsc secondary
no bsc secondary

Syntax Description

This command has no arguments or keywords.

Default

No default is specified.

Command Mode

Interface configuration

Usage Guidelines

The BSC support feature in this serial interface uses the address of the poll or selection block in the framing encapsulation. It also generates an EOT frame preceding each BSC poll and selection.

Example

The following example specifies the router as the secondary role:

bsc secondary

Related Command

bstun route

bsc servlim

Use the bsc servlim interface configuration command to specify the number of cycles of the active poll list that are performed between polls to control units in the inactive poll list. Use the no form of this command to cancel the specification.

bsc servlim servlim-count
no bsc servlim servlim-count

Syntax Description

servlim-count

Number of cycles.

Default

The default number of cycles is 3.

Command Mode

Interface configuration

Example

The following command sets the number of cycles to 2:

bsc servlim 2

bsc spec-poll

Use the bsc spec-poll interface configuration command to specify specific polls, rather than general polls, used on the host-to-router connection. Use the no form of this command to cancel the specification.

bsc spec-poll
no spec-poll

Syntax Description

This command has no arguments or keywords.

Default

No default is specified.

Command Mode

Interface configuration

Usage Guidelines

Use the bsc spec-poll command when a router is connected to a host, and only when that host issues specific polls rather than general polls. Tandem hosts that poll ATM cash machines are typically configured to use specific polls rather than general polls.

Configuring a downstream (control-unit/device connected) router to support specific polling has no effect.

Example

The following commands configure interface serial 0 to use specific poll:

interface serial 0

description Connection to host.

encapsulation bstun

bstun group 1

bsc secondary

bsc spec-poll

bsc char-set ebcdic

bstun route all tcp <ip-addr-of-remote-peer>

bstun group

Use the bstun group interface configuration command to specify the BSTUN group to which the interface belongs. Use the no form of this command to remove the interface from the BSTUN group.

bstun group group-number
no bstun group group-number

Syntax Description

group-number

The BSTUN group to which the interface belongs.

Default

No default is specified.

Command Mode

Interface configuration

Usage Guidelines

Each BSTUN-enabled interface on a router must be placed in a BSTUN group that was previously defined by the bstun protocol-group command. Packets only travel between BSTUN-enabled interfaces that are in the same group.

Example

The following example specifies that serial interface 0 belongs to the previously defined protocol group 1:

bstun group 1

Related Commands

bstun protocol-group
encapsulation bstun

bstun keepalive-count

Use the bstun keepalive-count global configuration command to define the number of times to attempt a peer connection before declaring the peer connection to be down. Use the no form of this command to cancel the definition.

bstun keepalive-count count
no bstun keepalive-count

Syntax Description

count

Number of connection attempts. The range is between 2 and 10 retries.

Default

No default is specified.

Command Mode

Global configuration

Example

The following example sets the number of times to retry a connection to a peer to 4:

bstun keepalive-count 4

Related Command

bstun remote-peer-keepalive

bstun peer-name

Use the bstun peer-name global configuration command to enable the block serial tunneling function. Use the no form of this command to disable the function.

bstun peer-name ip-address
no bstun peer-name ip-address

Syntax Description

ip-address

Address by which this BSTUN peer is known to other BSTUN peers that are using the TCP transport.

Default

No default is specified.

Command Mode

Global configuration

Usage Guidelines

The bstun peer-name command must be configured even if TCP transport is not used.

Example

The following example enables the block serial tunneling function:

bstun peer-name 150.10.254.201

Related Command

bstun protocol-group

bstun protocol-group

Use the bstun protocol-group global configuration command to define a BSTUN group, and the protocol it uses. Use the no form of this command to delete the BSTUN group.

bstun protocol-group group-number protocol {bsc | bsc-local-ack}
no bstun protocol-group group-number protocol {bsc | bsc-local-ack}

Syntax Description

group-number	The BSTUN group number. Valid numbers are decimal integers in the range 1 to 255.
protocol	Currently the only supported block serial protocol is bsc.
bsc	Enables BSC passthrough.
bsc-local-ack	Enables local acknowledgment of BSC frames.

Default

No defaults are specified.

Command Mode

Global configuration

Example

The following example assigns defines BSTUN group 1 and specifies that it uses the BSC protocol, and that frames will be locally acknowledged:

bstun protocol-group 1 bsc-local-ack

Related Command

bstun group

bstun remote-peer-keepalive

Use the bstun remote-peer-keepalive global configuration command to enable detection of the loss of a peer. Use the no form of this command to disable detection.

bstun remote-peer-keepalive seconds
no bstun remote-peer-keepalive

seconds

Keepalive interval, in seconds. The range is 1 to 300 seconds.

Syntax Description

Default

The default is 30 seconds

Command Mode

Global configuration

Example

In the following example, the remote-peer-keepalive interval is set to 60 seconds:

bstun remote-peer-keepalive 60

Related Command

bstun keepalive-count

bstun route

Use the bstun route interface configuration command to define how frames will be forwarded from a BSTUN interface. Use the no form of this command to cancel the definition.

bstun route {all | address address-number} {tcp ip-address | interface serial number} [direct]
no bstun route {all | address address-number} {tcp ip-address | interface serial number}
[direct]

Syntax Description

all	All BSTUN traffic received on the input interface is propagated, regardless of the address contained in the serial frame.
address	The serial frame that contains a specific address is propagated.
address-number	For BSC protocols, address number is the poll address.
tcp	TCP encapsulation is used to propagate frames that match the entry.
ip-address	The IP address of the remote BSTUN peer.
interface serial	HDLC encapsulation is used to propagate the serial frames.
number	The serial line to an appropriately configured router on the other end.
direct	(Optional) The specified interface is also a direct BSTUN link, rather than a serial connection to another peer.

Default

No defaults are specified.

Command Mode

Interface configuration

Example

The following example, all BSTUN traffic received on serial interface 0 is propagated, regardless of the address contained in the serial frame:

bstun route all interface serial 0

encapsulation bstun

Use the encapsulation bstun interface configuration command to configure BSTUN on a particular serial interface. Use the no form of this command to disable the BSTUN function on the interface.

encapsulation bstun
no encapsulation bstun

Syntax Description

This command has no arguments or keywords.

Default

No default is specified.

Command Mode

Interface configuration

Usage Guidelines

The encapsulation bstun command must be configured on an interface before any further BSTUN or BSC commands are configured for the interface.

You must use this command to enable BSTUN on an interface. Before using this command, complete the following two tasks:

•Enable BSTUN on a global basis by identifying BSTUN on IP addresses. The command is bstun peer-name.

•Define a protocol group number to be applied to the interface. Packets only travel between interfaces that are in the same protocol group. The command is bstun protocol-group.

After using the encapsulation bstun command, use the bstun group command to place the interface in the previously defined protocol group.

Example

The following example configures the BSTUN function on serial interface 1:

interface serial0

no ip address

encapsulation bstun

Related Command

bstun group
bstun peer-name
bstun protocol-group

encapsulation stun

Use the encapsulation stun interface configuration command to enable STUN encapsulation on a specified serial interface.

encapsulation stun

Syntax Description

This command has no arguments or keywords.

Default

STUN encapsulation is disabled

Command Mode

Interface configuration

Usage Guidelines

Use this command to enable STUN on an interface. Before using this command, complete the following two tasks:

•Enable STUN on a global basis by identifying STUN on IP addresses. The command is stun peer-name.

•Define a protocol group number to be applied to the interface. Packets only travel between interfaces that are in the same protocol group. The command is stun protocol-group.

After using the encapsulation stun command, use the stun group command to place the interface in the previously defined protocol group.

Example

This partial configuration example shows how to enable serial interface 5 for STUN traffic:

! sample stun peer name and stun protocol-group global commands 

stun peer-name 131.108.254.6

stun protocol-group 2 sdlc

! 

interface serial 5 

! sample ip address command

no ip address

! enable the interface for STUN; must specify encapsulation stun 

! command to further configure the interface 

encapsulation stun 

! place interface serial 5 in previously defined STUN group 2

stun group 2 

! enter stun route command 

stun route 7 tcp 131.108.254.7 

Related Commands

stun group
stun peer-name
stun protocol-group

locaddr-priority-list

Use the locaddr-priority-list interface configuration command to establish queuing priorities based upon the address of the logical unit (LU). Use the no form of this command to cancel all previous assignments.

locaddr-priority-list list-number address-number queue-keyword
no locaddr-priority-list

Syntax Description

list-number	Arbitrary integer between 1 and 10 that identifies the LU address priority list.
address-number	Value of the LOCADDR= parameter on the LU macro, which is a 1-byte address of the LU in hexadecimal.
queue-keyword	Priority queue type: high, medium, normal, or low.

Default

No queuing priorities are established.

Command Mode

Interface configuration

Example

The following example shows how to establish queuing priorities based on the address of the serial link on a STUN connection. Note that you must use the priority-group interface configuration command to assign a priority group to an input interface:

stun peer-name 131.108.254.6

stun protocol-group 1 sdlc 

!

interface serial 0

no ip address

encapsulation stun

stun group 1 

stun route address 4 interface serial 0 direct

locaddr priority 1

priority-group 1 

!

locaddr-priority-list 1 02 high

locaddr-priority-list 1 03 high

locaddr-priority-list 1 04 medium

locaddr-priority-list 1 05 low

Related Command

priority-group

priority-group

Use the priority-group interface configuration command to assign a priority group to an interface. Use the no form of this command to remove assignments.

priority-group list-number
no priority-group list-number

Syntax Description

list-number

Priority list number assigned to the interface.

Default

No priority group is assigned.

Command Mode

Interface configuration

Example

The following example shows how to establish queuing priorities based on the address of the serial link on a STUN connection. Note that you must use the priority-group interface configuration command to assign a priority group to an output interface.

! sample stun peer-name global command

stun peer-name 131.108.254.6

! sample protocol-group command for reference

stun protocol-group 1 sdlc 

! 

interface serial 0

! disable the ip address for interface serial 0

no ip address

! enable the interface for STUN

encapsulation stun

! sample stun group command 

stun group 2 

! sample stun route command 

stun route address 10 tcp 131.108.254.8 local-ack priority

! 

! assign priority group 1 to the input side of interface serial 0 

priority-group 1 

! assign a low priority to priority list 1 on serial link identified

! by group 2 and address A7 

priority-list 1 stun low address 2 A7 

Related Commands

locaddr-priority-list
priority-list protocol ip tcp
priority-list stun address

priority-list protocol bstun

Use the priority-list protocol bstun global configuration command to establish BSTUN queuing priorities based on the BSTUN header. Use the no form of this command to revert to normal priorities.

priority-list list-number protocol bstun queue [gt packetsize] [lt packetsize]
[address bstun-group bsc-addr]
no priority-list list-number protocol bstun queue [gt packetsize] [lt packetsize]
[address bstun-group bsc-addr]

Syntax Description

list-number	Arbitrary integer between 1 and 10 that identifies the priority list selected by the user.
queue	Priority queue type: high, medium, normal, or low.
gt | lt packetsize	(Optional) Output interface examines header information and packet size and places packets with the BSTUN header that match criteria gt or lt specified packet size) on specified output.
address bstun-group bsc-addr	(Optional) Output interface examines header information and BSC address and places packets with the BSTUN header that match BSC address on the specified output queue.

Default

Prioritize based on BSTUN header.

Command Mode

Global configuration

Example

In the following example, the output interface examines the header information and places packets with the BSTUN header on the output queue specified as medium.

priority-list 1 protocol bstun medium

Related Commands

encapsulation bstun

priority-list protocol ip tcp

Use the priority-list protocol ip tcp global configuration command to establish BSTUN or STUN queuing priorities based on the TCP port. Use the no form of this command to revert to normal priorities.

priority-list list-number protocol ip queue tcp tcp-port-number
no priority-list list-number protocol ip queue tcp tcp-port-number

Syntax Description

list-number	Arbitrary integer between 1 and 10 that identifies the priority list selected by the user.
queue	Priority queue type: high, medium, normal, or low.
tcp-port-number	BSTUN port and priority settings are as follows: High - BSTUN port 1976 Medium - BSTUN port 1977 Normal - BSTUN port 1978 Low - BSTUN port 1979 STUN port and priority settings are as follows: High - STUN port 1994 Medium - STUN port 1990 Normal - STUN port 1991 Low - STUN port 1992.

Default

The default is normal queue.

Command Mode

Global configuration

Usage Guidelines

Use the priority-list stun address command first. Priority settings created with this command are assigned to SDLC ports.

---

Note   SDLC local acknowledgment with the priority option must be enabled using the
stun route address tcp command.

---

Examples

In the following example, queuing priority for address C1 using priority list 1 is set to high. A priority queue of high is assigned to the SDLC port 1994.

priority-list 1 stun high address 1 C1

priority-list 1 protocol ip high tcp 1994

In the following example, queueing priority for address C1 using priority list 1 is set to high. A priority queue of high is assigned to BSTUN port 1976.

priority-list bstun high address 1 c1

priority-list 1 protocol ip high 1976

Related Commands

bstun protocol-group
priority-group
encapsulation bstun
encapsulation stun
priority-list stun address

priority-list stun address

Use the priority-list stun address global configuration command to establish STUN queuing priorities based on the address of the serial link. Use the no form of this command to revert to normal priorities.

priority-list list-number stun queue-keyword address group-number address-number
no priority-list list-number stun queue-keyword address group-number address-number

Syntax Description

list-number	Arbitrary integer between 1 and 10 that identifies the priority list selected by the user.
queue-keyword	Priority queue type: high, medium, normal, or low.
group-number	Group number that is used in the stun group command.
address-number	Address of the serial link. For an SDLC link, the format is a 1-byte hex value (for example, C1). For a non-SDLC link, the address format can be specified by the stun schema command.

Default

The default is normal queue.

Command Mode

Global configuration

Usage Guidelines

---

Note   SDLC local acknowledgment with the priority option must be enabled using the
stun route address interface serial command.

---

The priority-list command is described in greater detail in the "System Management Commands" chapter.

Example

In the following example, queuing priority for address C1 using priority list 1 is set to high:

priority-list 1 stun high address 1 C1

Related Commands

priority-list protocol ip tcp
stun group
stun schema offset length format

queue-list protocol bstun

Use the queue-list protocol bstun global configuration command to customize BSTUN queuing priorities based on the BSTUN header. Use the no form of this command to revert to normal priorities.

queue-list list-number protocol bstun queue [gt packetsize] [lt packetsize]
[address bstun-group bsc-addr]
no queue-list list-number protocol bstun queue [gt packetsize] [lt packetsize]
[address bstun-group bsc-addr]

Syntax Description

list-number	Arbitrary integer between 1 and 10 that identifies the priority list selected by the user.
queue	Priority queue type: high, medium, normal, or low.
gt | lt packetsize	(Optional) Output interface examines header information and packet size and places packets with the BSTUN header that match criteria gt or lt specified packet size) on specified output.
address bstun-group bsc-addr	(Optional) Output interface examines header information and BSC address and places packets with the BSTUN header that match BSC address on the specified output queue.

Default

Prioritize based on BSTUN header.

Command Mode

Global configuration

Example

In the following example, the output interface examines the header information and places packets with the BSTUN header on the output queue specified as medium.

queue-list 1 protocol bstun medium

Related Commands

encapsulation bstun

queue-list protocol ip tcp

Use the queue-list protocol ip tcp global configuration command to customize BSTUN or priorities based on the TCP port. Use the no form of this command to revert to normal priorities.

queue-list list-number protocol ip queue tcp tcp-port-number
no queue-list list-number protocol ip queue tcp tcp-port-number

Syntax Description

list-number	Arbitrary integer between 1 and 10 that identifies the priority list selected by the user.
queue	Priority queue type: high, medium, normal, or low.
tcp-port-number	BSTUN port and priority settings are as follows: High - BSTUN port 1976 Medium - BSTUN port 1977 Normal - BSTUN port 1978 Low - BSTUN port 1979 STUN port and priority settings are as follows: High - STUN port 1994 Medium - STUN port 1990 Normal - STUN port 1991 Low - STUN port 1992.

Default

The default is normal queue.

Command Mode

Global configuration

Example

In the following example, queueing priority for address C1 using priority list 1 is set to high. A priority queue of high is assigned to BSTUN port 1976.

queue-list bstun high address 1 c1

queue-list 1 protocol ip high 1976

Related Commands

encapsulation bstun

sdlc virtual-multidrop

Use the sdlc virtual-multidrop interface configuration command to allow SDLC broadcast address FF to be replicated for each of the STUN peers, so each of the end stations receive the broadcast frame. Use the no form of this command to disable the SDLC broadcast feature.

sdlc virtual-multidrop
no sdlc virtual-multidrop

Syntax Description

This command has no arguments or keywords.

Command Mode

Interface configuration

Example

The following example allows each STUN peer to receive a broadcast frame:

sdlc virtual-multidrop

Related Command

stun route address tcp

show bsc

Use the show bsc privileged EXEC command to display statistics about the interfaces on which BSC is configured.

show bsc

Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show bsc command:

Router# show bsc

BSC local-ack on Serial2: Poll mode is pollee. BSC State is CU_Idle.

Tx Counts: 0 frames(total). 0 frames(data). 0 bytes.

Rx Counts: 130218 frames(total). 0 frames(data). 390654 bytes.

Control units on this interface:

CU poll address: C1. Select address is 61. *CURRENT-CU*

CU state is: inactive.

Tx Counts: 0 frames(total). 0 frames(data). 0 bytes.

Rx Counts: 32504 frames(total). 0 frames(data). 162520 bytes.

CU poll address: 40. Select address is 60. 

CU state is: inactive.

Tx Counts: 0 frames(total). 0 frames(data). 0 bytes.

Rx Counts: 32504 frames(total). 0 frames(data). 162520 bytes.

show bstun

Use the show bstun privileged EXEC command to display the current status of STUN connections.

show bstun

Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show bstun command:

Router# show bstun

This peer: 192.195.80.161

Serial1 (group 1 [bsc]) 

state  rx-pkts  tx-pkts  drops

1 TCP 192.195.80.162 Open 50 0 0

In the display, the first entry reports proxy polling enabled for address 7 and that Serial 0 is running with modulus 8 on the primary side of the link. The link has received 20,334 packets, transmitted 86,440 packets, and dropped 5 packets.

describes significant fields shown in the output.

Table 27-1 Show BSTUN Field Descriptions

Field	Description
This peer	Lists the peer-name or address. The interface name (as defined by the description command), its BSTUN group number, and the protocol associated with the group are shown on the header line.
BSTUN address	Address or the word all if the default forwarding entry is specified, followed by a repeat of the group number given for the interface.
Type of link	Description of link, either a serial interface using Serial Transport (IF followed by interface name), or a TCP connection to a remote router (TCP followed by IP address).
state	State of the link: open is the normal, working state; direct indicates a direct link to another line, as specified with the direct keyword on the bstun route command.
rx_pkts	Number of received packets.
tx_pkts	Number of transmitted packets.
drops	Number of packets that for whatever reason had to be dropped.

show stun

Use the show stun privileged EXEC command to display the current status of STUN connections.

show stun

Syntax Description

This command has no arguments or keywords.

Command Mode

Privileged EXEC

Sample Display

The following is sample output from the show stun command:

Router# show stun

This peer: 131.108.10.1

Serial0 -- 3174 Controller for test lab (group 1 [sdlc])                	

		state	rx-pkts	tx-pkts	drops	poll

  7[ 1] IF Serial1         open     20334    86440      5  8P

 10[ 1] TCP 131.108.8.1    open      6771     7331      0

all[ 1] TCP 131.108.8.1    open    612301  2338550   1005

In the display, the first entry reports proxy polling enabled for address 7 and that Serial 0 is running with modulus 8 on the primary side of the link. The link has received 20,334 packets, transmitted 86,440 packets, and dropped 5 packets.

describes significant fields shown in the output.

Table 27-2 Show STUN Field Descriptions

Field	Description
This peer	Lists the peer-name or address. The interface name (as defined by the description command), its STUN group number, and the protocol associated with the group are shown on the header line.
STUN address	Address or the word all if the default forwarding entry is specified, followed by a repeat of the group number given for the interface.
Type of link	Description of link, either a serial interface using Serial Transport (IF followed by interface name), or a TCP connection to a remote router (TCP followed by IP address).
state	State of the link: open is the normal, working state; direct indicates a direct link to another line, as specified with the direct keyword on the stun route command.
rx_pkts	Number of received packets.
tx_pkts	Number of transmitted packets.
drops	Number of packets that for whatever reason had to be dropped.
poll	Report of the proxy poll parameters, if any. P indicates a primary and S indicates a secondary node. The number before the letter is the modulus of the link.

stun group

Use the stun group interface configuration command to place each STUN-enabled interface on a router in a previously defined STUN group. Use the no form of this command to remove an interface from a group.

stun group group-number
no stun group group-number

Syntax Description

group-number

Integer in the range 1 through 255.

Default

Disabled

Command Mode

Interface configuration

Usage Guidelines

Before using this command, complete the following steps: (1) Enable STUN on a global basis with the stun peer-name command (2) Define the protocol group in which you want to place this interface with the stun protocol-group command (3) Enable STUN on the interface using the encapsulation stun command.

Packets only travel between STUN-enabled interfaces that are in the same group. Once a given serial link is configured for the STUN function, it is no longer a shared multiprotocol link. All traffic that arrives on the link is transported to the corresponding peer as determined by the current STUN configuration.

Example

The following example places serial interface 0 in STUN group 2, which is defined to run the SDLC transport:

! sample stun peer-name global command

stun peer-name 131.108.254.6

! sample protocol-group command telling group 2 to use the SDLC protocol 

stun protocol-group 2 sdlc

!

interface serial 0

! sample ip address subcommand

no ip address

! sample encapsulation stun subcommand 

encapsulation stun

! place interface serial0 in previously defined STUN group 2

stun group 2 

! enter stun route command 

stun route 7 tcp 131.108.254.7

Related Commands

encapsulation stun
priority-list stun address
stun peer-name
stun protocol-group

stun keepalive-count

Use the stun keepalive-count global configuration command to define the number of times to attempt a peer connection before declaring the peer connection to be down. Use the no form of this command to cancel the definition.

stun keepalive-count count
no stun keepalive-count

Syntax Description

count

Number of connection attempts. The range is between 2 and 10 retries.

Default

No default is specified.

Command Mode

Global configuration

Example

The following example sets the number of times to retry a connection to a peer to 4:

stun keepalive-count 4

Related Command

stun remote-peer-keepalive

stun peer-name

Use the stun peer-name global configuration command to enable STUN for an IP address. Use the no form of this command to disable STUN for an IP address.

stun peer-name ip-address
no stun peer-name ip-address

Syntax Description

ip-address

IP address by which this STUN peer is known to other STUN peers.

Default

STUN is disabled

Command Mode

Global configuration

Usage Guidelines

Use this command to enable any further STUN features. After using this command, complete the following steps:

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Step 1 Define the protocol group in which you want to place this interface with the stun protocol-group command.

Step 2 Enable STUN on the interface using the encapsulation stun command.

Step 3 Place the interface in a STUN group with the stun group command.

Example

The following example assigns IP address 131.108.254.6 as the STUN peer:

stun peer-name 131.108.254.6

Related Commands

encapsulation stun
stun group
stun protocol-group

stun protocol-group

Use the stun protocol-group global configuration command to create a protocol group. Use the no form of this command to remove an interface from the group.

stun protocol-group group-number {basic | sdlc | schema} [sdlc-tg]
no stun protocol-group

Syntax Description

group-number	Integer in the range 1 through 255.
sdlc	Indicates an SDLC protocol.
basic	Indicates a non-SDLC protocol.
schema	Indicates a custom protocol.
sdlc-tg	(Optional) Identifies the group as part of an SNA transmission group.

Default

No protocol group established.

Command Mode

Global configuration

Usage Guidelines

Use the sdlc keyword to specify an SDLC protocol. You must specify either the sdlc or the sdlc-tg keyword before you can enable SDLC Local Acknowledgment. SDLC Local Acknowledgment is established with the stun route address tcp command.

Use the basic keyword to specify a non-SDLC protocol, such as HDLC.

Use the schema keyword to specify a custom protocol. (The custom protocol must have been previously created with the stun schema command.

Use the optional sdlc-tg keyword (in conjunction with the sdlc keyword) to establish an SNA transmission group. A transmission group is a set of protocol groups providing parallel links to the same pair of IBM establishment controllers. This provides redundancy of paths. In case one or more links go down, an alternate path will be used. All STUN connections in a transmission group must connect to the same IP address. SDLC Local Acknowledgment must be enabled.

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Note   If you specify the keyword sdlc in the stun protocol group command string, you cannot specify the stun route all command on that interface.

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Examples

The following example specifies that group 7 will use the SDLC STUN protocol to route frames within that group:

stun protocol-group 7 sdlc

The following example specifies that group 5 use the basic protocol, wherein the serial addressing is unimportant and you have a point-to-point link:

stun protocol-group 5 basic

Related Commands

encapsulation stun
stun route address interface serial
stun route address tcp
stun schema offset length format

stun quick-response

Use the stun quick-response global configuration command to enable STUN quick-response, which can be used with local acknowledgment. Use the no form of this command to disable STUN quick-response.

stun quick-response
no stun quick-response

Syntax Description

This command has no arguments or keywords.

Default

STUN quick-response is disabled.

Command Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.3(5).

This command is used with local acknowledgment (local ack).

When STUN quick-response is enabled, the router responds to an exchange identification (XID) or a Set Normal Response Mode (SNRM) request with a Disconnect Mode (DM) response when the device is not in the CONNECT state. The request is then passed to the remote router and, if the device responds, the reply is cached. The next time the device is sent an XID or SNRM, the router replies with the cached DM response.

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Note   Using STUN quick-response avoids an AS/400 line reset problem by eliminating the Non-Productive Receive Timer (NPR) expiration in the AS/400. With quick-response enabled, the AS/400 receives a response from the polled device, even when the device is down. If the device does not respond to the forwarded request, the router continues to respond with the cached DM response.

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Example

The following example enables STUN quick-response:

stun quick-response

Related Commands

You can use the master indexes or search online for documentation of related commands.

stun route address interface dlci
stun route address interface serial
stun route address tcp
stun route all interface serial
stun route all tcp

stun remote-peer-keepalive

Use the stun remote-peer-keepalive global configuration command to enable detection of the loss of a peer. Use the no form of this command to disable detection.

stun remote-peer-keepalive seconds
no stun remote-peer-keepalive

seconds

Keepalive interval, in seconds. The range is 1 to 300 seconds.

Syntax Description

Default

The default is 30 seconds

Command Mode

Global configuration

Example

In the following example, the remote-peer-keepalive interval is set to 60 seconds:

stun remote-peer-keepalive 60

Related Command

stun keepalive-count

stun route address interface dlci

Use the stun route address interface dlci interface configuration command to configure direct Frame Relay encapsulation between STUN peers with SDLC local acknowledgment. Use the no form of this command to disable the configuration.

stun route address sdlc-addr interface frame-relay-port dlci number localsap local-ack cls
no stun route address sdlc-addr interface frame-relay-port dlci number localsap local-ack cls

sdlc-addr	Address of the serial interface.
interface frame-relay-port	Port number.
dlci number	DLCI number.
localsap	Local connecting SAP.
local-ack	Enable local acknowledgment.
cls	Use Cisco Link Services (CLS) to access frame relay network.

Syntax Description

Default

The configuration is disabled.

Command Mode

Interface configuration

Example

The following command enables Frame Relay encapsulation between STUN peers with SDLC local acknowledgment:

stun route address C1 interface Serial1 dlci 22 04 local-ack

Related Command

stun route all interface serial

stun route address interface serial

Use the stun route address interface serial interface configuration command to forward all HDLC traffic on a serial interface. Use the no form of this command to disable this method of HDLC encapsulation.

stun route address address-number interface serial