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Video no.

7 (300-115)
Objective of this videos

 Understanding, configuring and verifying VLAN & trunk.
 Troubleshooting and managing VLAN database.

VLAN is layer 2 isolation of traffic (1VLAN=1 broadcast domain=1subnet) for better resource
utilization, QOS, logically groups users and security.

VLAN no.: VLAN no

Default VLAN
Extended range
Use for Ethernet

Not show on VLAN database
Can`t modified/delete, can use only
VTP modes must be transparent to use extended range of VLAN
Can be used and modified/delete if necessary for Ethernet LAN

Note no. of VLAN also depend on switch model.

Type of VLAN: Type of VLAN Descriptions
Use for normal data
Voice/axillary Use for IP phone/Voice over IP
Use for security , it divided primary and secondary VLAN
Management A VLAN which for Telnet, SSH for configuration
Nothing special but will usable if VTP mode is transparent on switches
Native VLAN
For backward compatibility, frame are untagged send over trunk link (by default VLAN1)
Note: - On topic of infra security will discuss more for Private VLAN in this series

Host/node assignment on VLAN: By port basis, port reserve for particular VLAN, manual assignment required every
time while assigning to other VLAN
By MAC address basic, more efficient utilization, any port can be used for any
VLAN (VMPS server required)
Note: - A single port can be used for Data and Voice VLAN as well

VLAN creation ways: 1) On global prompt
2) On VLAN database prompt
3) Directly assign interface to VLAN also create VLAN if not exists

VLAN port Roles: Switch port mode Access Description and works Belong to one VLAN for data can voice as well.If port Administrative mode is Auto/dynamic/desirable then it can be work as access or trunk by negotiation Troubleshooting Trunk port Switch#show interfaces f0/1 switchport Switch#show interfaces trunk . default is enable ) Dynamic auto Negotiation mode to for trunk and access (default role) Dynamic Desirable Negotiation mode but activity form trunk (available on higher series ) *Single port can be belong two different VLAN one for data other for Voice Note: . Deal with tagged & untagged frame (DTP can be disable for ISL and . not deal with tagged frame until IP phone connected to that port (disable DTP) Trunk Belong to multiple VLAN.1q tagging.Port Operational mode changes if port is Auto/desirable Valid mode of port to forming Trunk: Port role side A Access Access Access Dynamic auto Desirable Desirable Desirable Trunk Trunk Port role side B Access Trunk Desirable Dynamic auto Dynamic auto Desirable Trunk Dynamic auto Trunk Result No trunk form No trunk form No trunk form No trunk form Trunk form Trunk form Trunk form Trunk form Trunk form Administrative Mode V/S Operational Mode Configure to work as = Administrative Mode (define by Admin) Currently working as = Operational Mode (select by negotiation) Note: .

 Trunk port can be allow or deny particular VLAN data. and for negotiating the type of trunking encapsulation to be used. It works on the Layer 2 of the OSI model. IP camera etc.  A trunk link must have same native VLAN on both side.1q ISL IEEE (802.1Q or Cisco ISL trunking protocols. of VLAN Header size 4 bytes Trailer size N/A FCS and recalculation required CISCO proprietary No compatibility 1000 no. of VLAN 26 bytes 4 bytes Not required Dynamic Trunking Protocol (DTP) is a proprietary networking protocol developed by Cisco Systems for the purpose of negotiating trunking on a link between two VLANaware switches.  Access port is member of one data VLAN and voice VLAN if vice VLAN configured. VLAN trunks formed using DTP may utilize either IEEE 802. IP Phone.1q) Backward compatible (Native VLAN) Support 4095 no.Characteristics of trunk port & access port: Trunk port generally use for connect switches and router. Trunk encapsulation/tagging: .  Trunk port is member of all VLAN be default.  Access port use port connect end device (like Computer. .

Port may assign to VLAN so after rebooting switch find startup configuration with VLAN that not exist will create automatically These notes takes from CISCO/ Or e-mail us website then edited for this video For any assistance and query please visit .youtube.Port may trunk or assign to deleted/removed VLAN from database Problem) why VLAN automatic created after power recycle.Managing VLAN database and troubleshooting:  Removing VLAN  Unassigned port from VLAN /Default mode  Deleting VLAN database Problem) why port not shown while executed command SW1# show vlan Solution: . even after deleted from database & flash: Solution: .