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Chapter 3 Multiplayer
Terms in this set (100)
what is the purpose of native vlan?
The purpose of the native VLAN is to enable frames that are not tagged with a VID to traverse the trunk link.
what are some advantages of using 802.1q trunking protocol over ISL protocol.
1. smaller overhaead 4
2. wildly supported
3. 802.1q have the support of 802.1p filed for QoS
what does the Tag filed contain
1. vlan ID
2. Intertype (untagged Frames)
3. priority field (QoS)
4. CFI: Canonical Format Identifier
what are the two type of trunking technologies
1. 802.1 q ( industry standard)
2. Inter switch Link (cisco proprietor)
For a trunk to be enable and work properly what must be configure?
1. native vlan must match on both side
when is an 802.1q TAG is ignored?
when an access port receive a tag frame. all tag are strips off frames before they are send to the access link.
To process an 802.1Q tagged frame,
a device must enable a MTU of 1522 or higher.
what is the standard MTU size
what are baby giants frames
frames that are larger then the standard MTU size 1500 but not lager the 2000 bytes
what is the default size MTU for 802.1Q protcol and ISL protocols
802.1q default MTU is 1522
ISL default MTU is 1500
what are some problem that will occur because of mismatch native vlan?
1. connectivity issure
2. layer 2 loop may occur
Cisco switches use Cisco Discovery Protocol (CDP) to warn
of a native VLAN mismatch.
by default native vlan are vlan 1
native vlan are vlan 1
config of native vlan
Switch(config-if)# switchport trunk native vlan 1
what is DTP (Dynamic Trunking Protocol) Cisco proprietary
DTP is trunking protocol that negotiate trunking state. DTP negotiates the operational mode of directly connected switch ports to a trunk port. Negotiating trunking is a recommended practice in multilayer switched networks because it avoids network issues resulting from trunking misconfigurations
Dynamic Trunking Protocol
negotiates the operational mode of directly connected switch ports to a trunk port.
Cisco Trunking Modes and Methods
1. access- permanent nontrunking mode
2. trunk- permanent trunking mode
3. nonegotiate- prevent interface from generating DTP frames.
4. dynamic desirable- make the interface to actively attempt to covert the link to trunk link
5. dynamic auto- make the interface willing to convert the link to a trunk link
put the interface into permanent nontrunking mode and negotiates to convert the link into a nontrunk link. the interface become a nontrunk interface even if the neighboring interface does not agree to the change
put the interface into permanent trunking mode and negotiates to convert the link into a trunk link.
the interface become a trunk interface even if the neighboring interface does not agree to the change.
prevent interface from generating DTP frames. you must configure the local and neighboring interface manually as a trunk interface to establish a trunk link. use this mode when connecting to a device that does not support DTP.
make the interface to actively attempt to covert the link to trunk link. the interface become trunk interface if the neighboring interface is set to trunk, desirable, or auto mode.
make the interface willing to convert the link to a trunk link the interface become a trunk interface if the neighboring interface is set to trunk, desirable mode. this is the default mode for all Ethernet interface in Cisco ios
dynamic auto + dynamic auto
dynamic Desirable + dynamic desirable
what is the default behavior of vlan trunks?
is to permit all normal and extended-range vlan across the link
Best practices of vlans.
1. one to three vlans per access switches
2. avoid using vlan 1 as black hole
3. separate voice vlan and Data vlan
4. avoid VTP in local vlan
5. for trunking port turn off DTP
6. manually configure access port
7. prevent all data traffic from vlan 1
8. avoid using telnet
when is DTP is useful
when the status of the switch on the other end of the link is uncertain or might be changing over time
Best practices for trunk link
1. (Disable) prune the VLANs that are not used
have an unused VLAN as a native VLAN on the trunk links to prevent DTP spoofing.
VTP packets are sent to the
what is VTP
is a layer protocol that maintain vlan configuration. addition,deletion and change of name of vlan.
cisco switches sent vtp summary advertisement
over the management vlan ( by default vlan 1)
what state are Cisco switches in by default (VTP domain)
no management state or **
when can a Cisco switch get out of the default state? which is no management state or Null?
when the switch receive an advertisement for a domain or when the management domain is configure.
what is a vtp domain
VTP domain is one switch or several interconnected switches sharing the same VTP environment but switch can be only in one VTP domain at any time.
when are switches consider to be sharing the same domain?
when VTP domain and VTP Password match. when VTP password and VTP domain match exchange of information may start to take place.
what are the three VTP mode
1. can not create, modify or delete vlan.
2. send and forward advertisement
3. synchronize vlan configuration
1. create, modify and delete vlan
2. send and forward advertisement
3. synchronize vlan configuration
1. can create, modify and delete local vlan only.
2. forward advertisement.
3.does not synchronize vlan configuration
Vtp message are transmitted out of all trunks connection
vtp advertisement goes out on all trunks links.
where does vtp server and client save their vlan configured file by default?
in the vlan.dat file in the flash memory
what are thr three vtp version
version 1 default
the is the purpose of vtp pruned
it restrict unnecessary traffic from flooding the trunk links. and increases bandwidth availability
what all switches much match in order to be apart of a vtp doman?
1. all switches much have same passwork (MD5 16 byte) vtp password are Case Sensitive
2. same domain name.
what does the vtp summary advertisement contain
1. vtp password
2. domain name
3. revision number
what are VTP recommended best practice
2. configure all switches to transparent VTP mode
How often are vtp advertisement are sent
every 5 minute or every time a change occur to the vlan configured
what does a higher revision number indicate?
indicate the vlan information being advertised is the more current.
when does the revision number increase?
every time the vtp server modifies its vlan configuration file. (increase by one every time a change occur)
Transparent mode away have a revision number of
How does a switch become a server and not the client?
1. You manually configure the switch as a server
what are thing you can do to change the revision number
1. create a new vlan
2. change domain and back
3. change vtp mode to transparent and back to server mode.
What are the vtp Message type
1. Summary advertisement
2. Subset Advertisement
are sent to neighbor switches.
they are sent every five minute.
summary advertisement contain current revision number, domain name and password.
when will a summary advertisement packet be ignore
1. when the vtp domain name do not match
2. when a receiving switch have a higher revision number.
advertisement vlan information.
Subset advertisement make change to the revision number when adding or deletion occur on the vtp server, subset advertisement will sent a summary advertisement.
When does a switch sent a Advertisement Request?
1. when the switch has been reset.
2. when vtp domain name change.
3. when it recive a higher revision number then his own
what is the default domain name for vtp switches?
configuring VTP on switches
sw1(config)# vtp password Cisco
sw1(config)#vtp mode client
Sw1(config)#vtp domain Ccnp
sw1(config)vtp version 1
Show Vtp Status
it show you all the default configuration of vtp
How do you change the revision number to zero?
1. change vtp domain name and back
2. change vtp mode to transparent and back
when will vtp client send an advertisement
vtp client usually only listen to advertisement.
it will only sent advertisement when the switch was just added to the network.
what are some benefit to EtherChannel ?
1. Cheap, do not need to upgrade your entire infrastructure
2. Easy to configure, most of the configuration can take place on the etherchannel interface
3. it support load balancing.
What is the Purpose of Ether-channel
is to increase the speed or bandwidth between switches, by aggregating more then one physical link into one logical link.
on what ports can you configure EtherChannel?
On similar Port EX: 1. Trunk to Trunk
2. Access port to Access Port
what devices can ether channel be enable on?
Switch to Switch
Switch to Sever
EtherChannel has a logical port channel interface
A configuration that is applied to that logical port channel interface affects all physical interfaces that are assigned to that interface.
Link Aggregation control protocol (LACP)
allow switch to to negotiate an automatically bundle. LACP work in mix environment.
what is the highest number of physical link that can be bundle in an EtherChannel
16 but only 8 can be active at a time, Nonactive links are placed into a standby state and are enabled if one of the active links goes down.
How does a switch become Active or Passive
Priority Number (lower is better. lower priority mean active port.
1. Active ------ Enable LACP
2. Passive------ standby, only when an active go off line.
what is the Switch ID made of?
1. Switch priority
2. Mac- address
PAgP port mode
1. desirable: enable PAgp------- Cisco Priority
2. Auto: Standby
What must you do before implementing Ether-Channel (guideline )
1. identify which port you want to used for Ether-Channel
2. identify which Ether-channel protocol you want to used (LACP or PAgP)
3. After connection has be established make sure that Ether-Channel has Formed and proving aggregated bandwidth.
what will Cost an Ether-Channel not to formed
1. Mix match speed and duplex
2. mix match Vlan
3. Mix match Ether-Channel Protocol
(LACP & PAgP)
Ether-Channel Load Balancing
do not load balance traffic equally among ether- channel links.
The default hash for load Balancing is
show command to verify load-balancing
#show Port-channel Load-balance
A four-link bundle uses a hash of the
last 2 bits
A bundle of eight links uses a hash of the
last 3 bits.
What is the Purpose of Ether-Channel Guard
is use to detect ether-channel misconfiguration between switch and device.
when does Ether-channel misconfiguration occur
When ether-channel parameters do not match on both side of the ether-channel.
you will get the massage when ether-channel mis-configuration occur.
%PM-SP-4-ERR_DISABLE: channel-misconfig error detected on Po3, putting E1/3 in
use the #show spanning-tree summary
to verify if enther-channel guard is enable.
(Ether-Channel guard is enable by default)
Native Vlan handle untagged packets
Any packets that are sent across the trunk without tags, they will be place in the native vlan.
what is the default DTP mode for switches
what command will show you what DTP mode is running on a interface? (dynamic auto, dynamic desirable, auto, access, and tunk.
#show int fa0/1 switchport
Nonegotiate DTP mode
Do not sent DTP packets
Configuration of native vlan
sw(config)# name Native-Vlan
sw(config-if)#switchport trunk native vlan 15
What does VTP Pruning do
Allow you to automatically filter traffic. vtp only work on vtp server. VTP pruning is off by default.. vtp pruning prune broadcast traffic from reaching vlan.
steps to configuring VTP
1. Verity VTP status al all switches
2. configure vtp domain name / password
3.configure vtp mode
4. set vtp version number
5. verity VTP Status # show VTP status
What is the default Template for switches
what show command will show detail of the current template?
#show sdm prefer
what are two vlan State
1. Active state: the default state
2. suspended state: vlan exists but it does not operate. Access ports assigned to a suspended VLAN drop all frames and are unable to communicate
what is the different between vtp 1,2vs 3
vtp version 3 can only have one primary server present in the VTP domain.2. VTP version 3 has the ability to hide the VTP password. On a VTP version 1 or 2 switch, issuing the command show vtp password will show the password to you in plain text.
what devices does straight cable connect
different type device
ex: switch + Router
PC + Switch
switch to Server
When do you use a Cross-over cable
similar devices such as: Router + Router, Switch + Switch and so on
What does Auto MDI do?
automatically Detect cable type.
what is the default state of vlan
How do you put Vlan in an inactive state
by shutting down the vlan locally
ALS(config)#shutdown vlan 110
what are two command that will show you the current show version
1. #show run
2. show version
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