native vlan and control traffic...

i got involved in a thread on cln here:

https://learningnetwork.cisco.com/message/279101#279101

on that link you can download a packet capture that i attached...

i've read recently some conflicting ideas about the tagging of control traffic when vlan 1 is not present... my original thought sided with marko that l2 control traffic belonged to the switch.. here is marko's post:

http://blog.ipexpert.com/2011/01/19/old-ccie-myths-vlan-1/

he explores this idea at length, but this idea is incorrect...

this idea is refuted here:

http://www.fragmentationneeded.net/2011/01/revisiting-vlan-1-myth-again.html

and from the horse's mouth here:

(from Cisco Lan Switching Fundamentals)

It is important to understand the significance of VLAN 1. By default, all switch ports are part of VLAN 1. VLAN 1 contains control plane traffic and can contain user traffic. It is recommended that user traffic be configured on VLANs other than VLAN 1, primarily to prevent unnecessary user broadcast and multicast traffic from being processed by the Network Management Processor (NMP) of the supervisor. Although VLAN 1 user traffic can be pruned from a trunk, it is not the case with control plane traffic. In fact, in older Cisco Catalyst Software versions (5.4 or earlier), VLAN 1 could not be removed at all from a trunk. Control plane traffic such as VTP, CDP, and PAgP protocols are tagged with VLAN 1 information and are forwarded on a trunk regardless if the trunk has pruned VLAN 1.


naturally, i wanted to do my own testing, but my caps never showed tagging... i was using a dhcp windows client for monitoring and in the back of my mind my thought was that i'd never see dot1q tags because my windows nic simply didn't support tagging, therefore wouldn't show in the cap...  well, breaking my current working topology was an annoying idea simply to prove that so i moved on with what i was currently working at the time...

this morning, of course, it was nagging me so i had to be sure... turns out that is correct... dot1q tags don't show up in my windows box caps, but they do with the linux caps...

note on dsw1 in the below output that vlan 1 is not included in trunking...

dsw1#sh int trunk                                                              
                                                                               
Port        Mode             Encapsulation  Status        Native vlan          
Po1         on               802.1q         trunking      200                  
Po2         on               802.1q         trunking      200                  
                                                                               
Port        Vlans allowed on trunk                                             
Po1         10,20,200                                                          
Po2         10,20,200                                                          
                                                                               
Port        Vlans allowed and active in management domain                      
Po1         10,20,200                                                          
Po2         10,20,200                                                          
                                                                               
Port        Vlans in spanning tree forwarding state and not pruned             
Po1         10,20,200                                                          
Po2         10,20,200               

in the cap below note that the control traffic is tagged with vlan 1...

in fact all of the control traffic in the cap is tagged 1... but see for yourself, download the cap from the link and draw your own conclusions... also note that the cap is from the tshoot topology, which means that all supported protocols are represented as they would appear in cisco's topology...  naturally it is my representation of that topology; it is not gospel...

have fun...

note about topology: vlan's 4 and 8 support the gns3 environment onto the switched network... so don't let those qinq's confuse you...

vlan preschool...

it's baby time... grab your pablum and bibs... don't forget to drool...

here is an interesting thought...  you want to know the various devices connected via vlans from one switch, dls1 in this case... you have a number of commands that will help you assemble this information, you don't however have a command that will quickly map it out for you...

try and you'll see that you actually have to piece this information together... we have been in vlan denial all these years... show vlan doesn't give a shit about the trunks...

DLS1#sh vlan brie                                                              
                                                                               
VLAN Name                             Status    Ports                          
---- -------------------------------- --------- -------------------------------
1    default                          active                                   
10   OFFICE                           active                                   
20   VOICE                            active                                   
30   GUEST                            active                                   
50   SERVERS                          active    Fa0/6                          
100  MGMT                             active                                   
900  NATIVE                           active                                   
999  UNUSED                           active    Fa0/7, Fa0/8, Fa0/9, Fa0/10    
                                                Fa0/11, Fa0/12, Fa0/13, Fa0/14 
                                                Fa0/15, Fa0/16, Fa0/17, Fa0/18 
                                                Fa0/19, Fa0/20, Fa0/21, Fa0/22 
                                                Fa0/23, Fa0/24, Gi0/1, Gi0/2   

that's a start anyway...

DLS1#sh vlan id 50                                                             
                                                                               
VLAN Name                             Status    Ports                          
---- -------------------------------- --------- -------------------------------
50   SERVERS                          active    Fa0/6, Po10  

funny i never really thought about this... we have a lock on f0/6 and portchannel 10...  of course i know what devices they are connected to, but is the output giving it up...

DLS1#sh etherch summ | b Group                                                 
Group  Port-channel  Protocol    Ports                                         
------+-------------+-----------+-----------------------------------------------
1      Po1(SU)          -        Fa0/1(P)    Fa0/2(P)                          
10     Po10(SU)         -        Fa0/3(P)    Fa0/4(P)

po10 has f0/3 - 4, but what are they connected to, and would you ever rely on a description?

DLS1#sh int po10 trunk                                                         
                                                                               
Port        Mode             Encapsulation  Status        Native vlan          
Po10        on               802.1q         trunking      900                  
                                                                               
Port        Vlans allowed on trunk                                             
Po10        10,20,30,50,100                                                    
                                                                               
Port        Vlans allowed and active in management domain                      
Po10        10,20,30,50,100                                                    
                                                                               
Port        Vlans in spanning tree forwarding state and not pruned             
Po10        10,20,30,50,100                    

that's a great command... f0/3 - 4 are definitely supporting native vlan 900 as well as vlans 10,20,30,50 and 100...

DLS1#sh cdp neigh | b Device                                                   
Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID    
R1.tshoot.net    Fas 0/5           125             R S I  2611XM    Fas 0/0    
ALS1.tshoot.net  Fas 0/1           166              S I   WS-C3550- Fas 0/1    
ALS1.tshoot.net  Fas 0/2           166              S I   WS-C3550- Fas 0/2    
DLS2.tshoot.net  Fas 0/4           164             R S I  WS-C3560- Fas 0/4    
DLS2.tshoot.net  Fas 0/3           164             R S I  WS-C3560- Fas 0/3 

good ole faithful cdp neighbor, but what if it was turned off?

DLS1#sh int f0/4                                                               
FastEthernet0/4 is up, line protocol is up (connected)                         
  Hardware is Fast Ethernet, address is 0016.c706.9686 (bia 0016.c706.9686)    
  Description: Channel to DLS2

it's nice that the description is correct in this case... 

DLS1#sh int f0/4 sw                                                           
Name: Fa0/4                                                                   
Switchport: Enabled                                                           
Administrative Mode: trunk                                                    
Operational Mode: trunk (member of bundle Po10)  

ultimately this exercise brings up the importance of documentation, diagrams...

don't forget this command (although it is reliant on description and isn't a big help with the vlan to trunk connection)

DLS1#sh int status                                                             
                                                                               
Port      Name                         Status       Vlan       Duplex  Speed Type        
Fa0/1     Channel to ALS1    connected    trunk      a-full  a-100 10/100BaseTX
Fa0/2     Channel to ALS1    connected    trunk      a-full  a-100 10/100BaseTX
Fa0/3     Channel to DLS2    connected    trunk      a-full  a-100 10/100BaseTX
Fa0/4     Channel to DLS2    connected    trunk      a-full  a-100 10/100BaseTX
Fa0/5     FE to R1           connected    routed       full    100 10/100BaseTX
Fa0/6     FE to SRV1         notconnect   50           auto   auto 10/100BaseTX
Fa0/7     Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/8     Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/9     Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/10    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/11    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/12    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/13    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/14    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/15    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/16    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/17    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/18    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/19    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/20    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/21    Unused             disabled     999          auto   auto 10/100BaseTX
                                                                               
Port      Name               Status       Vlan       Duplex  Speed Type        
Fa0/22    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/23    Unused             disabled     999          auto   auto 10/100BaseTX
Fa0/24    Unused             disabled     999          auto   auto 10/100BaseTX
Gi0/1     Unused             disabled     999          auto   auto Not Present 
Gi0/2     Unused             disabled     999          auto   auto Not Present 
Po1       Channel to ALS1    connected    trunk      a-full  a-100             
Po10      Channel to DLS2    connected    trunk      a-full  a-100  

where is the command show vlans connected?

i have read that for the ccie lab you will be able to count on the documentation as well as the descriptions... but what about an evil proctor?

switch blueprint 001...

Determine network resources needed for implementing a VLAN based solution on a network

this is a nebulous topic and i think subjective... references i'm finding for this all point to common sense, or follow the guidance from the flg as being nearly the same, or see the quick study guide or look to the ppdioo....

ios/switches/routers/protocols/infrastructure
ip subnets/addressing and vlan associations
vlan numbers, names, locations,
trunking and protocol/placement/native vlan, vlans allowed
vtp (arghh) parameters if necessary (transparent)
testing and verification

as always, the correct answer is the cisco answer for testing purposes...

extended system id...

a fixed switch shares it's mac address with it's ports...

Base ethernet MAC Address: 00:09:B7:52:D7:80
the mac address of port 1 on this switch is:


asw2#sh int f0/1
FastEthernet0/1 is up, line protocol is up (connected)
  Hardware is Fast Ethernet, address is 0009.b752.d781 (bia 0009.b752.d781)

if your comfortable with hex, you can easily determine the rest of the ports mac addresses by counting up...


asw2#sh int f0/10
FastEthernet0/10 is down, line protocol is down (notconnect)
  Hardware is Fast Ethernet, address is 0009.b752.d78a (bia 0009.b752.d78a) = 10 hex

you knew that...

the default switch priority is 32768...

we know that the combination of priority and mac address gives us the BID
because 1 or many ports may belong to a vlan, we need more distinction...

the extended system id makes that yet more granular...


asw2#sh spann vlan 20

VLAN0020
  Spanning tree enabled protocol ieee
  Root ID    Priority    32788
             Address     0009.b73f.ce80 (base ethernet)
             Cost        38
             Port        2 (FastEthernet0/2)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32788  (priority 32768 sys-id-ext 20) 32768 + 20

the extended system id allows the vlan for the switch to have a unique BID

graphic below from http://adelzalok.wordpress.com/2011/09/29/anatomy-of-a-mac-address-bpdu-bid-and-the-802-1q-ethernet-frame-tag/  great site by the way... you haven't clicked on it yet?

svi v. vlan...

keith barker says that a switched virtual interface is a logical interface created from an existing vlan... this is an excellent explanation of this vague difference... here you can download that video in zip format, and i suggest you do....

https://learningnetwork.cisco.com/docs/DOC-7501

the only requirement to creat a vlan is a number, period... to further create the svi, you must type int vlan 99, after creating the vlan... there are no other requirements to creating the svi...


dsw2(config)#vlan 99
dsw2(config-vlan)#end
dsw2#sh vlan brie

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/6, Fa0/7, Fa0/8, Fa0/9
                                                Fa0/10, Fa0/11, Fa0/12, Fa0/13
                                                Fa0/14, Fa0/15, Fa0/16, Fa0/17
                                             
10   data                             active
20   voice                            active
99   VLAN0099                         active
100  mgmt                             active
1002 fddi-default                     act/unsup
1003 trcrf-default                    act/unsup
1004 fddinet-default                  act/unsup
1005 trbrf-default                    act/unsup

dsw2(config)#int vlan 99
dsw2(config-if)#do sh int vlan 99
Vlan99 is up, line protocol is down
  Hardware is EtherSVI, address is 000b.5fc9.0000 (bia 000b.5fc9.0000)
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

l2 to l3/bridging the gap...

  a vlan is a layer 2 construct, a pointer to layer 3, an association by layer 2 to layer 3...
vlan=network=subnet=broadcast domain

  a broadcast domain is the set of devices which may receive broadcasts... a layer 3 device is the defining element of the broadcast domain... a switch creates more and smaller collision domains with each additional port it places within the domain... a layer 3 device creates an additional broadcast domain with each port it introduces...  a switch floods broadcasts, multi-casts and unknown unicasts to every device in the domain... a layer 3 device recieves all broadcasts from a connected switch, and drops them (unless otherwise defined)... a layer 3 device defines the broadcast domain with that action...this layer 3 device is affectionately known as a router... vlan=network=subnet=broadcast domain


  a vlan number is the only requirement when creating a vlan. of course it's fairly useless without ports added to it, and a descriptive name would be nice also, but these are not required...

  an end-to-end vlan spans the entire switched network and should be avoided as such, a local vlan remains local (within its group) and is preferred...

  a vlan trunk can carry multiple vlans' traffic across the network

 isl encapsulates a frame for tagged transit whereas the preferred method of tagging is 802.1q, which injects a 4 byte field into the frame... 802.1q does not tag the native vlan; the native vlan is identified by the lack of a tag...

  dtp is dynamic trunking protocol.  it is a trunking negotiation mechanism...

  the native vlan is a settable parameter and is vlan1 by default... it is recommended to change the native vlan to something other than 1 after bringing the switch up... it is important to match the native vlans between switches to avoid annoying cdp messages, and sometimes derailed traffic...

cst...

common spanning tree

the original iteration of  802.1q defined a single instance of spanning tree regardless of the amount of vlans; a common tree for the entire network.  when a path is blocked due to convergence, as it will be, there is but one path for the vlans to traverse toward their destination.

this is hardly fair for the multiple vlans that could potentially take more than one path if given the opportunity.

so the common tree does not allow for load balancing although this is ultimately less cpu intensive.

enter mst

by definition mst supports multiple trees similar to pvst, which supports an instance per vlan.  however, unlike pvst, a reduction in the total amount of instances can be achieved by balancing, grouping, vlans together and shipping them across different paths; many vlans; less instances; less cpu cycles...

shit's getting deep... baby steps...

he-lans...

vlan tagging and 802.1q

802.1q introduced the concept of the native vlan. the native vlan passes untagged frames
and are recognized as belonging to it as such.  other vlans are tagged, thereby
identified, via a two byte tag identifier or TPID which always has a value of 0x8100
(802.1q tag) and another two bytes are used for Tag Control Information (TCI), bringing the total to 4
bytes.  the tci contains a 3 bit priority field (PCP, priority code point) to identify class of service
(COS) and a 12 bit VID (vlan identifier). the single bit remaining and sandwiched between
the pcp and vid is the canonical format identifier (allowing compatibility for ethernet and
token ring). this will be set to 0 for ethernet (if it is set to 1, token ring, you are
working on a network from the last century) I actually supported a token ring network in
the 90's and it was great--back then.

802.1q does not encapsulate the frame although some authors refer to it as such.  it adds
(injects) this two byte field between the source mac and ether type field.  encapsulation
of frames for vlan identification is the purview of that other thing (isl) that cisco
should finally make go away and stop mentioning in cisco press books.

DTP as well as VTP are technologies that also should go away... Are you going to trust your
trunks to discover each other... no... are you going to deploy a new switch without
configuring the proper vlans... no... of course, no... will you save bandwidth and retain
your sanity... yes

even mentioning these things, you can almost see the authors cringing;

    "On critical trunk links in a network, manually configuring the trunking mode on both    
    ends is best so that the link never can be negotiated to any other state."

when is a trunk not critical... good Lord... it's embarrassing...

phoneys...

there are three  ports on a given ip phone (at least on cisco phones)... they are serial (rs-232), switch and pc... the serial port is used for an expansion module, guess what the switch port is used for, guess what the pc port is used for?... so we know that the switch port will attach to the switch port on the phone and the pc port will attach from the phone to the pc...  how can this be since we know from our long hard studies in ccna universe that we can't carry multiple vlans across an access port, so that's it...  it's a trunk...  so use crossed cables for the devices and set up the switchport as a trunk...  actually, no...

the switchport is still configured as an access port, and the cables used are straight through... but we want to segregate the voice and data traffic, and how can we do that on an access port with a straight through cable...  what would father Odom say?

the phone is equipped with switch like hardware that allows it to receive and send tags...  the phone (switch) creates a trunk... this allows for data traffic (untagged) to be forwarded correctly while the voice vlan traffic is forwarded (tagged) with it's vlan...

an access port that supports vlans... shit...

vtp why?

a switch in your network fails and needs to be replaced... you get a new one next day, what do you do?  take it out of the box, slap a console cable on it, rev it up, configure it with a hostname, give it a default gateway, give it a management vlan and ip address, password protect the vty's and console, assign the vlans and ports as access to those vlans, assign the trunk ports where necessary, manually to trunk mode, copy run start and put it in the closet...  this takes about five minutes...

and what about vtp... turn that shit off...


sw2950_02(config)#int vlan 5
sw2950_02(config-if)#vtp mode off
                     ^
% Invalid input detected at '^' marker.

sw2950_02(config-if)#vtp mode trans
Setting device to VTP TRANSPARENT mode.
sw2950_02(config)#

whoops...
wait, i think i'll create a new vlan today and propagate it across the network from my vtp server.. no...

what if i want to use isl?  don't...

set the access ports to portfast, the trunks to on and stp to rapid-...

so why did i spend all this time learning these things...  so you know to turn that shit off...

vtputt-putt...

normally processing of commands from the CLI happens as soon as you press enter... not so with VTP when creating a vlan... not until you exit will the command process, as seen below...

sw3550_01#debug sw-vlan vtp events
vtp events debugging is on
sw3550_01#term mon
sw3550_01#config t
sw3550_01(config)#vlan 69
sw3550_01(config-vlan)#do sh vlan brie

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/2, Fa0/4, Fa0/5, Fa0/7
                                                Fa0/8, Fa0/9, Fa0/10, Fa0/11
                                                Fa0/12, Fa0/13, Fa0/14, Fa0/15
                                                Fa0/16, Fa0/17, Fa0/18, Fa0/19
                                                Fa0/20, Fa0/22, Fa0/23, Fa0/24
                                                Gi0/1, Gi0/2
23   VLAN0023                         active
1002 fddi-default                     act/unsup
1003 trcrf-default                    act/unsup
1004 fddinet-default                  act/unsup
1005 trbrf-default                    act/unsup

sw3550_01(config-vlan)#exit
sw3550_01(config)#
now we get our debug output
Dec 27 20:10:40.615: VTP LOG RUNTIME: Transmit vtp summary, domain cisco, rev 13
, followers 1, tlv blk size 8 (inc #tlv field),
   MD5 digest calculated = 8D F5 FD E6 E2 18 EB 99 BD AC F8 2F 8B C5 00 DD

Dec 27 20:10:40.615: VTP LOG RUNTIME: Transmit vtp summary, domain cisco, rev 13
, followers 1, tlv blk size 8 (inc #tlv field),
   MD5 digest calculated = 8D F5 FD E6 E2 18 EB 99 BD AC F8 2F 8B C5 00 DD

Dec 27 20:10:40.615: VTP LOG RUNTIME: Transmit vtp summary, domain cisco, rev 13
, followers 1, tlv blk size 8 (inc #tlv field),
   MD5 digest calculated = 8D F5 FD E6 E2 18 EB 99 BD AC F8 2F 8B C5 00 DD

Dec 27 20:10:40.675: VTP LOG RUNTIME: Summary packet received, domain = cisco, r
ev = 13, followers = 1, length 80, trunk Fa0/1

Dec 27 20:10:40.675: VTP LOG RUNTIME: Validate TLVs : #tlvs 1, max blk size 4
Dec 27 20:10:40.675: VTP LOG RUNTIME: Validate TLVs : #00, val 6, len 4
Dec 27 20:10:40.675: VTP LOG RUNTIME: Summary packet rev 13 equal to domain cisc
o rev 13

Dec 27 20:10:40.679: VTP LOG RUNTIME: Subset packet received, domain = cisco, re
v = 13, seq = 1, length = 220

Dec 27 20:10:40.679: VTP LOG RUNTIME: Summary packet received, domain = cisco, r
ev = 13, followers = 1, length 80, trunk Fa0/3

sw3550_01(config)#
Dec 27 20:10:40.679: VTP LOG RUNTIME: Validate TLVs : #tlvs 1, max blk size 4
Dec 27 20:10:40.679: VTP LOG RUNTIME: Validate TLVs : #00, val 6, len 4
Dec 27 20:10:40.679: VTP LOG RUNTIME: Summary packet rev 13 equal to domain cisc
o rev 13

Dec 27 20:10:40.683: VTP LOG RUNTIME: Subset packet received, domain = cisco, re
v = 13, seq = 1, length = 220


sw3550_01(config)#do sh vlan brie
VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/2, Fa0/4, Fa0/5, Fa0/7
                                                Fa0/8, Fa0/9, Fa0/10, Fa0/11
                                                Fa0/12, Fa0/13, Fa0/14, Fa0/15
                                                Fa0/16, Fa0/17, Fa0/18, Fa0/19
                                                Fa0/20, Fa0/22, Fa0/23, Fa0/24
                                                Gi0/1, Gi0/2
23   VLAN0023                         active
69   VLAN0069                         active1002 fddi-default                     act/unsup
1003 trcrf-default                    act/unsup
1004 fddinet-default                  act/unsup
1005 trbrf-default                    act/unsup
sw3550_01(config)#


so much for command processing love...

router on a tip...

it doesn't get easier than this...

get a router a switch and 2 pc's...
connect a straight through cable from the router to a port on a switch... remove the ip address from the fa0/0 first and always, when making subinterfaces (frame and ppp too)... make two subinterfaces on the router
encap dot1q 21 means what it says; encapsulation dot1q for vlan 21...
give each sub ip's on different subnets (intervlan routing; now i got a network boner)


r2620_02#config t
Enter configuration commands, one per line.  End with CNTL/Z.
r2620_02(config)#int fa0/0.21
r2620_02(config-subif)#encap dot1q 21
r2620_02(config-subif)#ip add 192.168.21.1 255.255.255.0
r2620_02(config-subif)#no shut
r2620_02(config-subif)#int fa0/0.22
r2620_02(config-subif)#encap dot1q 22
r2620_02(config-subif)#ip add 192.168.22.1 255.255.255.0
r2620_02(config-subif)#no shut
r2620_02(config-subif)#

swich time..
make two vlans, make a trunk (assigning vlans to the trunk is optional, why, because they forward all vlan traffic by default unless otherwise slapped around), put an interface into each vlan and you got...

s2(config)#vlan 21
s2(config-vlan)#name 21
s2(config-vlan)#vlan 22
s2(config-vlan)#name 22
s2(config-vlan)#exit
s2(config)#int fa0/17
s2(config-if)#sw mode trunk
s2(config-if)#sw trunk allow vlan 21,22
s2(config-if)#exit
s2(config)#int fa0/15
s2(config-if)#sw mode acc
s2(config-if)#sw acc vlan 21
s2(config-if)#int fa0/16
s2(config-if)#sw mode acc
s2(config-if)#sw acc vlan 22
s2(config-if)#do sh vlan

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/5
10   fac/staff                        active    Fa0/11, Fa0/12, Fa0/13, Fa0/14
20   students                         active    Fa0/18, Fa0/19, Fa0/20, Fa0/21
                                                Fa0/22, Fa0/23, Fa0/24
21   21                               active    Fa0/15
22   22                               active    Fa0/16

connect a pc to each switch port and set ip's and gateways...

and then ping the damn things... don't forget to debug ip icmp on the router, see after pc pings...

C:\Users\bosgood>ping 192.168.21.1

Pinging 192.168.21.1 with 32 bytes of data:
Reply from 192.168.21.1: bytes=32 time=2ms TTL=255
Reply from 192.168.21.1: bytes=32 time=1ms TTL=255
Reply from 192.168.21.1: bytes=32 time=1ms TTL=255
Reply from 192.168.21.1: bytes=32 time=2ms TTL=255

Ping statistics for 192.168.21.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 2ms, Average = 1ms


C:\Users\bosgood>ping 192.168.22.1

Pinging 192.168.22.1 with 32 bytes of data:
Reply from 192.168.22.1: bytes=32 time=2ms TTL=255
Reply from 192.168.22.1: bytes=32 time=2ms TTL=255
Reply from 192.168.22.1: bytes=32 time=1ms TTL=255
Reply from 192.168.22.1: bytes=32 time=1ms TTL=255

Ping statistics for 192.168.22.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 2ms, Average = 1ms

r2620_02#debug ip icmp
ICMP packet debugging is on
r2620_02#
Dec 22 18:47:13.575: ICMP: echo reply sent, src 192.168.21.1, dst 192.168.21.2
r2620_02#
Dec 22 18:47:14.575: ICMP: echo reply sent, src 192.168.21.1, dst 192.168.21.2
r2620_02#
Dec 22 18:47:15.579: ICMP: echo reply sent, src 192.168.21.1, dst 192.168.21.2
r2620_02#
Dec 22 18:47:16.583: ICMP: echo reply sent, src 192.168.21.1, dst 192.168.21.2

r2620_02#
Dec 22 18:49:39.983: ICMP: echo reply sent, src 192.168.22.1, dst 192.168.22.2
r2620_02#
Dec 22 18:49:40.987: ICMP: echo reply sent, src 192.168.22.1, dst 192.168.22.2
r2620_02#
Dec 22 18:49:41.987: ICMP: echo reply sent, src 192.168.22.1, dst 192.168.22.2
r2620_02#
Dec 22 18:49:42.991: ICMP: echo reply sent, src 192.168.22.1, dst 192.168.22.2
r2620_02#

that's a router on my...

rapid-pvst

it's stp per vlan, and faster... go figure...  yes virginia, every vlan has it's own christmas tree with a load balancing ornament on top...  tuning the priority will allow some of the members of the vlan to use one of the supported links while other members of the vlan will use the one's normally blocked by stp, instead of all using the same forwarding link...

all output guaranteed from my NOHO...  (new office home office)

sw2950_02#sh spann vlan 2

VLAN0002
  Spanning tree enabled protocol rstp
  Root ID    Priority    32770
             Address     0009.b73f.ce80
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32770  (priority 32768 sys-id-ext 2)
             Address     0009.b73f.ce80
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1            Desg BLK 19        128.1    P2p
Fa0/2            Desg BLK 19        128.2    P2p
Fa0/9            Desg BLK 19        128.9    P2p
Fa0/23          Desg FWD 19        128.23   P2p
Fa0/24          Desg BLK 19        128.24   P2p

a minor adjustment gives us this...

sw2950_02#config t
Enter configuration commands, one per line.  End with CNTL/Z.
sw2950_02(config)#int fa0/24
sw2950_02(config-if)#spann vlan 2 port-priority 0
sw2950_02(config-if)#end
sw2950_02#
2w0d: %SYS-5-CONFIG_I: Configured from console by console
sw2950_02#sh spann vl 2

VLAN0002
  Spanning tree enabled protocol rstp
  Root ID    Priority    4098
             Address     0009.b73f.ce80
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    4098   (priority 4096 sys-id-ext 2)
             Address     0009.b73f.ce80
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Fa0/1            Desg FWD 19        128.1    P2p
Fa0/2            Desg FWD 19        128.2    P2p
Fa0/9            Desg FWD 19        128.9    P2p
Fa0/23          Desg FWD 19        128.23   P2p
Fa0/24          Desg FWD 19          0.24   P2p

sw2950_02#

aaaaaahhhhhhhhhhhhh...

saran wrap...

when you receive a cisco switch it is by default set to server mode out of the box...  be sure to set it to transparent mode before deployment...

Server
 can create, add, delete  and/or change vlan information.  these changes are added throughout the VTP domain

Client
  listen for advertisements and modify their own configurations as a result.  a server is required by the client    for vlan changes. a client cannot create, add or delete vlans

Transparent
  can forward or receive vlan advertisements but otherwise do not participate in the domain...

you can see right through them... so there...

OZLAN...

the last day and a half has been enlightening... i used to support a large cisco network for many years, and the needs of that community... those needs were not my needs but i still had some great experiences...  having my own equipment and doing with it exactly as i want allows unlimited freedom... there is only so much experimentation one can do under production circumstances...

i have my 2950's and 2620's currently running rip and communicating with each other and the internet... i'll soon move on to ripv2, eigrp, ospf, etc... i have vlans  for hosts and printers, trunks are up and running, serial connections are singing, and i couldn't be happier...  also, if you have a chance to get your hands on a 3550 or 3560, beg borrow or steal...

this is a new phase for me, and as i move to different protocols with OZLAN and make new configurations, i'll erase start on all the devices, and rebuild them as if it was all new again... and you will all feel the pain with me...