VTP Client/ Server Behavior

[samat]

The Sever sends a VTP summary update
The Client's VTP revision number is higher than of VTP server
Question, explain how client will respond?

Whereas, to my knowledge the database of the VTP server should be synchronized to the one of the VTP client, whatever it contains in it will be passed to the server, because the revision number is lower. However, as far as i remember, you cannot add, remove or do any change in the client mode. This is a little a bit confusing.
Thanks,

[dbeare]

Router B will ignore the advertisement, as its revision number is higher than that of Router A. Client mode simply means that they can only send and receive updates, they can't make any changes, but if the revision number on the client is greater than the one that is being advertised by a VTP server, it will ignore the advertisement from that server.

[dbeare]

Also, I would highly advise against posting material from a well known brain dump on this site...but that's just me.

[samat]

Also, I would highly advise against posting material from a well known brain dump on this site...but that's just me.

Thanks,
Yeah, I guess you are right I should not post these material.

[VoIPTeK]

In a class I was in awhile ago, I was told a client switch can update a server switch if the client's revision number is higher than the server. Is this true? From the testing I've done in my home lab, I'd say it was false.

Switch_A#sh vtp status
VTP Version : 2
Configuration Revision : 2
Maximum VLANs supported locally : 254
Number of existing VLANs : 8
VTP Operating Mode : Server
VTP Domain Name : slacklab
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0xA1 0x44 0xAF 0xF8 0x36 0xE6 0xD1 0x73
Configuration last modified by 192.168.1.10 at 11-30-09 22:16:14

Switch_B#sh vtp status
VTP Version : 2
Configuration Revision : 2
Maximum VLANs supported locally : 254
Number of existing VLANs : 8
VTP Operating Mode : Client
VTP Domain Name : slacklab
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0xA1 0x44 0xAF 0xF8 0x36 0xE6 0xD1 0x73
Configuration last modified by 192.168.1.10 at 11-30-09 22:16:14

Switch_C#sh vtp status
VTP Version : 2
Configuration Revision : 3
Maximum VLANs supported locally : 254
Number of existing VLANs : 7
VTP Operating Mode : Client
VTP Domain Name : slacklab
VTP Pruning Mode : Disabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x94 0xA9 0xFF 0xCF 0x29 0xF2 0x12 0x2A
Configuration last modified by 192.168.1.10 at 3-3-93 19:27:27


When I run a debug, it looks like switch C won’t take it due to the revision #. However when I run the same debug in switch A, I don't see any VTP packets received as I do on Switch C. So to me, it seems like the client switch with the higher revision # will *not* send updates to the server switch. Is this correct?


00:10:44: VTP LOG RUNTIME: Transmit vtp summary, domain slacklab, rev 2, followers 0, tlv blk size 8 (inc #tlv field),
MD5 digest calculated = A1 44 AF F8 36 E6 D1 73 EF 29 42 89 DA F6 2B 90

00:10:45: VTP LOG RUNTIME: Transmit vtp summary, domain slacklab, rev 2, followers 0, tlv blk size 8 (inc #tlv field),
MD5 digest calculated = A1 44 AF F8 36 E6 D1 73 EF 29 42 89 DA F6 2B 90

00:10:45: VTP LOG RUNTIME: Transmit vtp summary, domain slacklab, rev 2, followers 0, tlv blk size 8 (inc #tlv fi
Switch_A#eld),
MD5 digest calculated = A1 44 AF F8 36 E6 D1 73 EF 29 42 89 DA F6 2B 90

[VoIPTeK]

In a class I was in awhile ago, I was told a client switch can update a server switch if the client's revision number is higher than the server. Is this true? From the testing I've done in my home lab, I'd say it was false.


I actually found the answer.. After further troubleshooting, I think something was corrupt in my vlan databases. I deleted the vlan database in all three switches. I then had Switch_A as the server and Switch_B and C as the client. I then disabled the trunk port on switch C, changed it to a server, added VLANS (which updates the revision #), changed it back to Client and unblocked the trunk port. Running a debug in Switch A (server mode) then confirmed it received an update from Switch_C (client mode).

Switch_A#
16:15:34: VTP LOG RUNTIME: Transmit vtp summary, domain slacklab, rev 5, followers 0, tlv blk size 8 (inc #tlv field),
MD5 digest calculated = AD 54 61 7E AF BF 4F 90 44 03 AB A3 23 1C D8 EF

16:15:34: VTP LOG RUNTIME: Transmit vtp summary, domain slacklab, rev 5, followers 0, tlv blk size 8 (inc #tlv field),
MD5 digest calculated = AD 54 61 7E AF BF 4F 90 44 03 AB A3 23 1C D8 EF

16:15:34: VTP LOG RUNTIME: Summary packet received, d_length = 8, domain = slacklab, rev = 6, followers = 0, leng
Switch_A#th 80, trunk Fa0/2

16:15:34: VTP LOG RUNTIME: Validate TLVs : #tlvs 1, max blk size 4
16:15:34: VTP LOG RUNTIME: Validate TLVs : #00, val 6, len 4
16:15:34:
16:15:34: summary: 02 01 00 08 73 6C 61 63 6B 6C 61 62 00 00 00 00 ....slacklab....
16:15:34: summary: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
16:15:34: summary: 00 00 00 00 00 00 00 06 C0 A8 01 0C 30 39 31 32 ........@(..0912
Switch_A# summary: 30 31 31 34 34 39 35 31 FF C3 E4 9E 82 31 A1 54 01144951.Cd..1!T
16:15:34: summary: 58 37 81 5D AB 56 BA 83 00 00 00 01 06 01 00 02 X7.]+V:.........
16:15:34:
16:15:34: VTP LOG RUNTIME: Summary packet rev 6 greater than domain slacklab rev 5

16:15:34: VTP LOG RUNTIME: Domain slacklab currently not in updating state

16:15:34: VTP LOG RUNTIME: Summary packet with followers field zero

16:15:34: VTP LOG RUNTIME: Transmit vtp request, domain slacklab, start value 0

16:15:34: VTP LOG RUNTIME: Summary packet received, d_length = 8, domain = slacklab, rev = 5
Switch_A#, followers = 0, length 80, trunk Fa0/1

16:15:34: VTP LOG RUNTIME: Validate TLVs : #tlvs 1, max blk size 4
16:15:34: VTP LOG RUNTIME: Validate TLVs : #00, val 6, len 4
16:15:34:
16:15:34: summary: 02 01 00 08 73 6C 61 63 6B 6C 61 62 00 00 00 00 ....slacklab....
16:15:34: summary: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
16:15:34: summary: 00 00 00 00 00 00 00 05 C0 A8 01 0C 30 39 31 32 ........@(..0912
16:15:34: summary: 30 31 31 34 33 36 33 33 AD 54 61 7E AF BF 4F 9
Switch_A#0 01143633-Ta~/?O.
16:15:34: summary: 44 03 AB A3 23 1C D8 EF 00 00 00 01 06 01 00 02 D.+##.Xo........
16:15:34:
16:15:34: VTP LOG RUNTIME: Summary packet rev 5 equal to domain slacklab rev 5
16:15:35: VTP LOG RUNTIME: Summary packet rev 6 greater than domain slacklab rev 5
16:15:35:
Switch_A# VTP LOG RUNTIME: Domain slacklab currently not in updating state
16:15:35: VTP LOG RUNTIME: pdu len 80, #tlvs 1
16:15:35: VTP LOG RUNTIME: Subset packet received, domain = slacklab, rev = 6, seq = 1, length = 256
16:15:35:
16:15:35: subset: 02 02 01 08 73 6C 61 63 6B 6C 61 62 00 00 00 00 ....slacklab....
16:15:35: subset: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
16:15:35: subset: 00 00 00 00 00 00 00 06 14 00 01 07 00 01 05 DC ...............\
16:15:35: subset:
Switch_A#00 01 86 A1 64 65 66 61 75 6C 74 00 14 00 01 06 ...!default.....
16:15:35: subset: 00 0A 05 DC 00 01 86 AA 47 61 6D 65 72 5A 00 00 ...\...*GamerZ..
16:15:35: subset: 14 00 01 07 00 14 05 DC 00 01 86 B4 48 61 63 6B .......\...4Hack
16:15:35: subset: 65 72 5A 00 10 00 01 04 00 32 05 DC 00 01 86 D2 erZ......2.\...R
16:15:35: subset: 56 6F 49 50 18 00 02 0C 03 EA 05 DC 00 01 8A 8A VoIP.....j.\....
16:15:35: subset: 66 64 64 69 2D 64 65 66 61 75 6C 74 30 00 03 0D fddi-default0...
16:15:35: sub
Switch_A#set: 03 EB 11 78 00 01 8A 8B 74 72 63 72 66 2D 64 65 .k.x....trcrf-de
16:15:35: subset: 66 61 75 6C 74 00 00 00 01 01 0C CC 04 01 03 ED fault......L...m
16:15:35: subset: 07 01 00 02 08 01 00 07 09 01 00 07 20 00 04 0F ............ ...
16:15:35: subset: 03 EC 05 DC 00 01 8A 8C 66 64 64 69 6E 65 74 2D .l.\....fddinet-
16:15:35: subset: 64 65 66 61 75 6C 74 00 03 01 00 01 24 00 05 0D default.....$...
16:15:35: subset: 03 ED 11 78 00 01 8A 8D 74 72 62 72 66 2D 64 65 .m.x....trbrf-de
16:15:35
Switch_A#: subset: 66 61 75 6C 74 00 00 00 02 01 00 0F 03 01 00 02 fault...........

[olatunji]

@ voiptek i tried this scenero but i got the same answer but we learn that switch in client mode cant update another switch but can only recieve update. please explain .

[Fuzz]

There is always confusion on this subject. The truth is that a client can update a server if it's revision number is higher. The difference between the client and server remains that a client cannot edit the vlan.dat database, nor can it change VTP data, such as domain name.

Remember that all data, apart from the revision number, must match between two switches for an update to the VLAN database to occur between them.

Take a look at these posts on the subject

http://www.networkworld.com/community/node/19931
http://www.networkworld.com/community/node/20017

[Javed.s]

Does anybody know if you can get your CCNP if your CCNA expired?
Or must you recertify your CCNA first?

[Fuzz]

CCNA is a prerequisite for CCNP, so you will have to have an active CCNA to attain CCNP certification