mls switchport... the suspense is killing me...

when you change a switchport's mode on an mls, you must change it back to switchport mode before using it as a l2 port again...

to make an mls port a l3 port, you must take it out of l2 mode first and always...

no switchport...

now it is unusable at only l2...

dls1(config)#int f0/15                                                          
dls1(config-if)#no sw                                                           
dls1(config-if)#sw mode acc                                                     
Command rejected: Fa0/15 not a switching port.                                  
dls1(config-if)#sw                                                              
dls1(config-if)#sw mode acc                                                     
dls1(config-if)#

you knew that... so did i...

you can suspend a vlan... in the suspend state it will not pass packets, but will retain its configuration... this might come in handy for troubleshooting, although i can't quite think of a reason...

dls1(config)#vlan 200                                                          
dls1(config-vlan)#state suspend                                                
dls1(config-vlan)#end                                                          
dls1#sh vlan id 200                                                            
                                                                               
VLAN Name                             Status    Ports                          
---- -------------------------------- --------- -------------------------------
200  VLAN0200                         suspended Fa0/7, Fa0/8, Fa0/9, Fa0/10    
                                                Fa0/11, Fa0/12                 
                                                                               
VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1 Trans2 
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 
200  enet  100200     1522  -      -      -        -    -        0      0      
                                                                           
don't forget to un suspend it, and put the mtu back to the default after you're finished dicking around so you don't get punished...

dls1(config)#vlan 200                                                          
dls1(config-vlan)#no state suspend                                             
dls1(config-vlan)#no mtu 1522                                                  
dls1(config-vlan)#end                                                          
dls1#sh vlan id 200                                                            
                                                                               
VLAN Name                             Status    Ports                          
---- -------------------------------- --------- -------------------------------
200  VLAN0200                         active    Fa0/7, Fa0/8, Fa0/9, Fa0/10    
                                                Fa0/11, Fa0/12                 
                                                                               
VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1 Trans2 
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------ 
200  enet  100200     1500  -      -      -        -    -        0      0      
                                                                            

channel-g...

i used a channel group between the 2 dsw's with an ip address configured directly on each end, as in the topology... 2 xover cables that had been previously configured for trunking... note the no switchport command and the lack of pagp or lacp negotiation...  a case can be made for negotiation because it will prevent inadvertently causing an errdisable to occur...  if you are certain both ports are configured the same, negotiation is really academic, for the purists of the bunch... lacp may come in handy for connecting to servers that are lacp capable...


dsw1#sh run int fa0/1
Building configuration...

Current configuration : 112 bytes
!
interface FastEthernet0/1
 no switchport
 no ip address
 speed 100
 duplex full
 channel-group 1 mode on


dsw1#sh run int po1
Building configuration...

Current configuration : 84 bytes
!
interface Port-channel1
 no switchport
 ip address 10.1.4.13 255.255.255.252
end

dsw1#


dsw2#sh run int po1
Building configuration...

Current configuration : 84 bytes
!
interface Port-channel1
 no switchport
 ip address 10.1.4.14 255.255.255.252
end


dsw1#sh int po1
Port-channel1 is up, line protocol is up (connected)
  Hardware is EtherChannel, address is 000f.8ffe.0980 (bia 000f.8ffe.0980)
  Internet address is 10.1.4.13/30


you get the idea...

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...

junk in the trunk...

sw2950_02(config)#int fa0/2
sw2950_02(config-if)#switchport nonegotiate
first, DTP (dynamic trunking protocol) is cisco proprietary and will not work with gray market switches...  use nonegotiate in a mixed environment... this disables DTP, will only become a trunk with ON or NONEGOTIATE ports, and  port ranges are not allowed with this command

sw2950_02(config)#int fa0/2
sw2950_02(config-if)#sw mode trunk
trunking is on... DTP signals are sent to the other connected port to initiate trunking if it is ON, AUTO, or DESIRABLE

if:
sw2950_02(config-if)#sw mode dynamic desirable
the port will become a trunk after detecting DTP signals of  ON, AUTO or DESIRABLE from the connected port

if:
sw2950_02(config-if)#sw mod dyn auto
the port will become a trunk if the other port is ON or DESIRABLE

if:
sw2950_02(config-if)#no sw mod trunk
trunking and DTP are disabled and this is the desired state for access ports; no dynamic establishments can occur

today's post was brought to you by Michael the network cat...

Guster the love muffin...

 and Craze, the queen of the domain...