Imagine you are sending a packet form one device to another. After the packet being processed with software queue, if any, then it is passed to hardware queue. Hardware queue will break it down to particles depends how much the length of the hardware queue consist.

R1#sh controllers f0/0 | i tx_limited
 tx_limited=0(64)

From the example above, FastEthernet 0/0 has can holds 16 particles as it is the length of FastEthernet 0/0 transmit queue available.

The number 0 shown above implies that the size of the queue is not limited (0 means false).

Now, we can actually tweak the number of the particles (Wendell Odom explains this using the word ‘packets length’) using command tx-ring-limit

R1(config)#int f0/0
R1(config-if)#tx-ring-limit 32
R1(config-if)#do sh controller f0/0 | i tx_limited
 tx_limited=0(32)

Sources.

• Understanding and Tuning the tx-ring-limit Value
• Cisco QOS Exam Certification Guide (IP Telephony Self-Study), 2nd Edition

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To find the network design guidance you need for a specific data center project, go to the CVD-I tab and navigate the topology.

To access the test descriptions, results, and device configuration of the latest fully test data center network architecture, go to the CVD-II tab.

Navigate the topology to find the test and configurations associated with any specific solution or device.

http://www.cisco.com/cdc_content_elements/flash/dcap3/

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Why am I getting these overlapping errors?

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In my previous post I threw out a few thoughts about the idea of enticing users to switch to IPv6 – a sort of variation on the long-running “we need an IPv6 killer app” argument – and the contradictions such enticement efforts would present: Mainly that IP of any version should be transparent to end-users who only care about services, not how those services are delivered. Any enticements bring IPv6 into the spotlight, where it should not be (except for routing and infrastructure geeks like me).

Looking at the other side of this transparency issue, just getting IPv6 rolled out brings unwanted attention to it: Users might have to upgrade operating systems, and might encounter problems reaching some destinations and services as the public Internet becomes split between an IPv4 world and an IPv6 world.

Read more from IPv6 at the 2008 Olympics by Jeff Doyle.

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Victor Cappuccio. CCIE Number: 20657
http://vcappuccio.wordpress.com/2008/04/30/ccie-number-20657/

Ethan Banks. CCIE #20655
http://www.cciecandidate.com/?p=412

and

Triple CCIE
Joe Harris. CCIE # 6200 (R&S, Security & SP)
http://6200networks.com/2008/04/27/i-passed/

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http://www.artlebedev.com/everything/optimus-tactus/

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For complete art appreciation, visit http://www.chrisjordan.com/current_set2.php?id=7

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Default OSPF hello and dead intervals is 10 seconds and 40 seconds, respectively.

• Partial-mesh or star network topology, using subinterface.
• Different subnet for each subinterface.
• Hello Timer 10 seconds.
• Automatic adjacency, no DR/BDR elected.

R1#sh run | b 1/0
interface Serial1/0
 no ip address
 encapsulation frame-relay
 serial restart-delay 0
!
interface Serial1/0.102 point-to-point
 ip address 192.168.102.1 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 102
!
interface Serial1/0.103 point-to-point
 ip address 192.168.103.1 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 103   

R1#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           0   FULL/  -        00:00:34    192.168.103.2   Serial1/0.103
2.2.2.2           0   FULL/  -        00:00:32    192.168.102.2   Serial1/0.102

R1#sh ip ospf int s1/0.102
Serial1/0.102 is up, line protocol is up
  Internet Address 192.168.102.1/30, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:06
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 4 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 2.2.2.2
  Suppress hello for 0 neighbor(s)

R1#sh ip ospf int s1/0.103
Serial1/0.103 is up, line protocol is up
  Internet Address 192.168.103.1/30, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:04
  Supports Link-local Signaling (LLS)
  Index 3/3, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 3.3.3.3
  Suppress hello for 0 neighbor(s)

R2#debug ip ospf hello
OSPF hello events debugging is on
R2#
*Mar  1 04:48:33.414: OSPF: Rcv hello from 1.1.1.1 area 0 from Serial1/0.201 192.168.102.1
*Mar  1 04:48:33.418: OSPF: End of hello processing
*Mar  1 04:48:37.458: OSPF: Send hello to 224.0.0.5 area 0 on Serial1/0.201 from 192.168.102.2
*Mar  1 04:48:37.462: OSPF: Send hello to 224.0.0.5 area 0 on Serial1/0.203 from 192.168.203.1
*Mar  1 04:48:41.002: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial1/0.203 192.168.203.2
*Mar  1 04:48:41.002: OSPF: End of hello processing

R2#sh run | b 1/0
interface Serial1/0
 no ip address
 encapsulation frame-relay
!
interface Serial1/0.201 point-to-point
 ip address 192.168.102.2 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 201
!
interface Serial1/0.203 point-to-point
 ip address 192.168.203.1 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 203   

R2#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           0   FULL/  -        00:00:33    192.168.203.2   Serial1/0.203
1.1.1.1           0   FULL/  -        00:00:35    192.168.102.1   Serial1/0.201

R2#sh ip ospf int s1/0.201
Serial1/0.201 is up, line protocol is up
  Internet Address 192.168.102.2/30, Area 0
  Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:09
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 1.1.1.1
  Suppress hello for 0 neighbor(s)

R2#sh ip ospf int s1/0.203
Serial1/0.203 is up, line protocol is up
  Internet Address 192.168.203.1/30, Area 0
  Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:07
  Supports Link-local Signaling (LLS)
  Index 3/3, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 3.3.3.3
  Suppress hello for 0 neighbor(s)

R3#sh run | b 1/0
interface Serial1/0
 no ip address
 encapsulation frame-relay
 serial restart-delay 0
!
interface Serial1/0.301 point-to-point
 ip address 192.168.103.2 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 301
!
interface Serial1/0.302 point-to-point
 ip address 192.168.203.2 255.255.255.252
 ip ospf network point-to-point
 snmp trap link-status
 frame-relay interface-dlci 302   

R3#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           0   FULL/  -        00:00:39    192.168.203.1   Serial1/0.302
1.1.1.1           0   FULL/  -        00:00:36    192.168.103.1   Serial1/0.301

R3#sh ip ospf int s1/0.301
Serial1/0.301 is up, line protocol is up
  Internet Address 192.168.103.2/30, Area 0
  Process ID 1, Router ID 3.3.3.3, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:01
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 1.1.1.1
  Suppress hello for 0 neighbor(s)

R3#sh ip ospf int s1/0.302
Serial1/0.302 is up, line protocol is up
  Internet Address 192.168.203.2/30, Area 0
  Process ID 1, Router ID 3.3.3.3, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:00
  Supports Link-local Signaling (LLS)
  Index 3/3, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 2.2.2.2
  Suppress hello for 0 neighbor(s)

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R1#sh run int s1/0
Building configuration...

Current configuration : 287 bytes
!
interface Serial1/0
 ip address 192.168.1.1 255.255.255.0
 encapsulation frame-relay
 ip ospf network point-to-multipoint non-broadcast
 serial restart-delay 0
 frame-relay map ip 192.168.1.2 102 broadcast
 frame-relay map ip 192.168.1.3 103 broadcast
 no frame-relay inverse-arp
end

R1#sh run | s router ospf
router ospf 1
 log-adjacency-changes
 network 1.1.1.1 0.0.0.0 area 0
 network 192.168.1.0 0.0.0.255 area 0
 neighbor 192.168.1.3
 neighbor 192.168.1.2
R1#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           0   FULL/  -        00:01:49    192.168.1.3     Serial1/0
2.2.2.2           0   FULL/  -        00:01:33    192.168.1.2     Serial1/0
R1#sh ip ospf int s1/0
Serial1/0 is up, line protocol is up
  Internet Address 192.168.1.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_MULTIPOINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,
  Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
    oob-resync timeout 120
    Hello due in 00:00:12
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0×0(0)/0×0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 4 msec
  Neighbor Count is 2, Adjacent neighbor count is 2
    Adjacent with neighbor 3.3.3.3
    Adjacent with neighbor 2.2.2.2
  Suppress hello for 0 neighbor(s)

R2#sh run int
*Mar  1 03:18:35.475: %SYS-5-CONFIG_I: Configured from console by console s1/0
Building configuration...

Current configuration : 287 bytes
!
interface Serial1/0
 ip address 192.168.1.2 255.255.255.0
 encapsulation frame-relay
 ip ospf network point-to-multipoint non-broadcast
 serial restart-delay 0
 frame-relay map ip 192.168.1.1 201 broadcast
 frame-relay map ip 192.168.1.3 203 broadcast
 no frame-relay inverse-arp
end

R2#sh run | s router ospf
router ospf 1
 log-adjacency-changes
 network 2.2.2.2 0.0.0.0 area 0
 network 192.168.1.0 0.0.0.255 area 0
 neighbor 192.168.1.3
 neighbor 192.168.1.1
R2#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           0   FULL/  -        00:01:30    192.168.1.3     Serial1/0
1.1.1.1           0   FULL/  -        00:01:57    192.168.1.1     Serial1/0

R3#sh run int s1/0
Building configuration...

Current configuration : 287 bytes
!
interface Serial1/0
 ip address 192.168.1.3 255.255.255.0
 encapsulation frame-relay
 ip ospf network point-to-multipoint non-broadcast
 serial restart-delay 0
 frame-relay map ip 192.168.1.1 301 broadcast
 frame-relay map ip 192.168.1.2 302 broadcast
 no frame-relay inverse-arp
end

R3#sh run | s router ospf
router ospf 1
 log-adjacency-changes
 network 3.3.3.3 0.0.0.0 area 0
 network 192.168.1.0 0.0.0.255 area 0
 neighbor 192.168.1.1
 neighbor 192.168.1.2
R3#sh ip ospf nei

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           0   FULL/  -        00:01:45    192.168.1.1     Serial1/0
2.2.2.2           0   FULL/  -        00:01:31    192.168.1.2     Serial1/0

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