Number of Spanning Tree instances per VLAN?
r_durant
Member Posts: 486 ■■■□□□□□□□
in CCNA & CCENT
TestOut says...
802.1q only supports one instance per VLAN
ISL supports multiple
Odom says in the Intro book...
Both 802.1q and ISL allows a spanning tree instance
Actually, the question in the Intro is pretty vague...
Which of the following allows a spanning tree instance per VLAN?
a. VTP
b. ISL
c. 802.1q
d. Both ISL and 802.1q
e. None of the above
I choose C, because I figured a to mean one instance...
The book goes on to say that one of the stated differences between the two trunking protocols was that 802.1q did not support multiple spanning trees...
I know both of them supports at least 1 instance, so I'm assuming that it's a trick question and that ISL supports multiple and 802.1q only supports 1...
802.1q only supports one instance per VLAN
ISL supports multiple
Odom says in the Intro book...
Both 802.1q and ISL allows a spanning tree instance
Actually, the question in the Intro is pretty vague...
Which of the following allows a spanning tree instance per VLAN?
a. VTP
b. ISL
c. 802.1q
d. Both ISL and 802.1q
e. None of the above
I choose C, because I figured a to mean one instance...
The book goes on to say that one of the stated differences between the two trunking protocols was that 802.1q did not support multiple spanning trees...
I know both of them supports at least 1 instance, so I'm assuming that it's a trick question and that ISL supports multiple and 802.1q only supports 1...
CCNA (Expired...), MCSE, CWNA, BSc Computer Science
Working on renewing CCNA!
Working on renewing CCNA!
Comments
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Netstudent
Member Posts: 1,693 ■■■□□□□□□□
Both can support a spanning tree insatnce for each VLAN. ISL uses PVST and dot1q uses PVST+
There are a couple good STP threads going in the CCNP forum that will probably answer your question.There is no place like 127.0.0.1 BUT 209.62.5.3 is my 127.0.0.1 away from 127.0.0.1! -
dtlokee
Member Posts: 2,378 ■■■■□□□□□□
The 802.1q standard supports 1 instance of STP for all VLANs, but who is Cisco to follow a standard? Cisco uses PVST+ for 802.1q trunks allowing a singles instance fore each VLAN.The only easy day was yesterday!