Network Security Wiki

BGP OSPF Questions: Difference between revisions

Page Discussion

BGP OSPF Questions (view source)

Revision as of 03:14, 22 June 2021

13 bytes added ,  2 years ago
→‎STP
Line 538:
 
== STP ==
* STP-is used to avoid unwanted loops in the environment.▼
* STP created one refernce point in n/w that is called root of tree ,based on rerfernce point decides whether there is redundant path in the n/w ▼
* Layer 2 forwading -By default CAM table entries got aged out every 300 sec ▼
* We can also create static mac address table entry in cam - command ( mac-address-table static mac-address VLAN id interface type )▼
 
▲* STP- is used to avoid unwanted loops in the environment.
▲* STP created one refernce point in n/w that is called root of tree , based on rerfernce point decides whether there is redundant path in the n/w .
▲* Layer 2 forwading - By default CAM table entries got aged out every 300 sec
▲* We can also create static mac address table entry in cam - command ( mac-address-table static mac-address VLAN id interface type )
 
* Bridge segments collsion domain dose not segmets broadcast doamin .▼
 
* Root bridge - selection is based on bPDU contains bridge id which is combination of mac address and priorty (both are chosen lower ) on root bridge both the ports are DP.▼
▲Bridge segments collsion domain dose not segmets broadcast doamin
then* Then there is selection of root port on non root bridge .▼
for* For root port selection is based on following paramteters ( lower root bride id , lowest path to root brige, ,lowest sender bridge id , lowest port priority, ,lowest port id .▼
for* For every lan segment -there is secltion of DP (selection is based on root id creteria)▼
 
* 802.1d states:
▲Root bridge -selection is based on bPDU contains bridge id which is combination of mac address and priorty (both are chosen lower )
Disabled
on root bridge both the ports are DP.
Blocking (listen to incoming BPDU)
▲then there is selection of root port on non root bridge .
Listening
Learning
Forwading (tranmit BPDU)
 
* Hello time - Default is 2 seconds , time interval in which subsequent configration BPDU send root bridge , for non root bridge TCN BPDU is 2 sec .▼
▲for root port selection is based on following paramteters ( lower root bride id ,lowest path to root brige ,lowest sender bridge id ,lowest port priority ,lowest port id .
* Forward delay - time interval swich port spends in listening and learning states , default time is 15 second .▼
* Maximum age -- time when max age is timed out is 20 seconds when the BPDU is aged out .▼
* In case if any interface flap ( up /down states ) switch will send the TCN BPDU untill it reach root bridge , root bridge will send the configration BPDU with TC flag set and each switch will will rebuild its mac table based on forwarding delay time. Default is 300 sec. Total time is 17 seconds.▼
total* Total time the port trantion from blocking to forwadig state is 30 seconds▼
 
* Port fast feature -when When we enable port fast on the port so TCN BPDU is send in case of Topolgy change and port directly transtion to forwading state .SO So there are chances that port fast enabled port could cause STP loops if the accidently switch is installed on that port , to prevnetprevent this we use BPDU Guard along with STP.▼
 
* We can manully select the root bridge -spanning tree VLAn vlanid priotry (bridge priority):▼
▲for every lan segment -there is secltion of DP (selection is based on root id creteria)
spanning tree VLAn vlanid priotry (bridge priority)
 
we* We can set mannualy to become one bridge to be root bridge ( spanning tree vlan vlan id root (primary ,secondary,diameter):▼
802.1d states -Disabled ,blocking?(listen to incoming BPDU) ,listening ,learning ,forwading (tranmit BPDU)
spanning tree vlan vlanid root (primary, secondary, diameter)
 
* We can aslo set the path cost -spanning tree vlan vlanid cost :▼
▲Hello time -Default is 2 seconds ,time interval in which subsequent configration BPDU send root bridge ,for non root bridge TCN BPDU is 2 sec .
spanning tree vlan vlanid cost
 
port* Port id is 16 bit -8 bit port priorty + 8 bit port number ▼
▲Forward delay -time interval swich port spends in listening and learning states ,default time is 15 second
spannin spanning tree vlan vlan idvlanid port priority ▼
 
▲Maximum age --time when max age is timed out is 20 seconds when the BPDU is aged out .
 
 
▲In case if any interface flap ( up /down states )switch will send the TCN BPDU untill it reach root bridge ,root bridge will send the configration BPDU with TC flag set and each switch
will will rebuild its mac table based on forwadig delay time .(default is 300 sec) total time is 17 seconds.
 
▲total time the port trantion from blocking to forwadig state is 30 seconds
 
 
▲Port fast feature -when we enable port fast on the port so TCN BPDU is send in case of Topolgy change and port directly transtion to forwading state .SO there are chances that port fast enabled port could cause STP loops if the accidently switch is installed on that port ,to prevnet this we use BPDU Guard along with STP.
 
 
▲We can manully select the root bridge -spanning tree VLAn vlanid priotry (bridge priority)
 
▲we can set mannualy to become one bridge to be root bridge ( spanning tree vlan vlan id root (primary ,secondary,diameter)
 
▲We can aslo set the path cost -spanning tree vlan vlanid cost
 
▲port id is 16 bit -8 bit port priorty + 8 bit port number
 
▲spannin tree vlan vlan id port priority
 
== RSTP ==
Retrieved from "https://aman.awiki.org/wiki/Special:MobileDiff/4443"