03-25-2008 07:56 AM - edited 03-05-2019 09:57 PM
this is output of sh int command
sh int
Vlan3 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description:
Internet address is 10.163.40.225/28
MTU 1500 bytes, BW 1000000 Kbit, DLY Encapsulation ARPA, loopback not set
Vlan4 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description:
Vlan7 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description:
Internet address is 10.180.0.1/30
Vlan9 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description:
Internet address is 10.180.0.6/30
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
output hang never
Last clearing of "show interface" counters never
Vlan12 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description: BTRadianz - London Stock Exchange Feed
Internet address is 10.180.0.9/29
buffers swapped out
Vlan17 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description: S2E - CFT Axway
Internet address is 10.180.0.18/30
ARP type: ARPA, ARP Timeout 04:00:00
Vlan100 is administratively down, line protocol is down
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description: Swift/Crest backup
Vlan101 is up, line protocol is up
Hardware is Cat6k RP Virtual Ethernet, address is 000f.35e0.7bfc (bia 000f.35e0.7bfc)
Description: Swift Crest SAG VPN
Internet address is 192.168.0.174/29
Input queue: 0/75/4/2 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue :0/40 (size/max)
5 minute input rate 2000 bits/sec, 2 packets/sec
5 minute output rate 2000 bits/sec, 2 packets/sec
182518373 packets input, 2626452751 bytes, 0 no buffer
Received 23918852 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
167599924 packets output, 2621003072 bytes, 0 underruns
0 output errors, 2 interface resets
0 output buffer failures, 0 output buffers swapped out
Loopback0 is up, line protocol is up
Hardware is Loopback
Internet address is 10.163.40.14/32
MTU 1514 bytes, BW 8000000 Kbit, DLY 5000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation LOOPBACK, loopback not set
Last input 43w6d, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue :0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
4 packets output, 2416 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
My question is w ehave different IP address for vlans but why we have same Mac-address for all vlans?
If someone can explain we this ?
Solved! Go to Solution.
03-25-2008 01:18 PM
by design, your physical interfaces on your switch will have a unique L2 mac address assigned to it. Your Logical Vlan interfaces (SVI) will share the same mac address assigned by the hardware by design.
Franco.
03-25-2008 09:10 AM
VLAN's are vitual interfaces that must have a seperate IP address.
The only way to keep them seperate is by IP addresses, like any other inerface you would use, you cannot have the same network assigned to different interfaces on the same device. In this case your VLAN, just as the name implies is virtual. It must be assigned with some type of layer 2 address so the rest of the layer devices know where it is at.
Is this what you were looking for?
03-25-2008 09:30 AM
when i do this command
sh vlans
No Virtual LANs configured.
it shows no virtual vlans config
why it says no virtual vlans config
03-25-2008 09:31 AM
VLAN = Virtual Local Area Network
03-25-2008 10:03 AM
Hi Engagerocks,
A simple explaination would be A VLAN do not have a mac address as it's virtual and not physical, this is why it will use the mac address of the interface it will use to transport the vlan.
HTH, Please rate
Regards,
Justin
03-25-2008 10:10 AM
Hi justin,
thanks for your answer
for e.g vlan 9 has one physical port
and vlan 12 has 3 physical ports so it will
use mac address of these switch ports to pass
the traffic
03-25-2008 10:31 AM
That is exactly what was said.
See previous post.
03-25-2008 10:48 AM
03-25-2008 11:35 AM
hi thanks for you reply.
so now we have this
vlan7 with mac address 000f.35e0.7bfc (bia 000f.35e0.7bfc)
port 3/3 is in vlan7.
i did
sh port mac-address 3/3
Port Mac address
----- -----------------
3/3 00-0f-f7-16-99-52
so this mac address is of switch port 3/3 right?
then i did
sh cam dynamic 3/3
* = Static Entry. + = Permanent Entry. # = System Entry. R = Router Entry.
X = Port Security Entry $ = Dot1x Security Entry
VLAN Dest MAC/Route Des [CoS] Destination Ports or VCs / [Protocol Type]
---- ------------------ ----- -------------------------------------------
7 00-0b-fc-c4-b4-08 3/3 [ALL]
Total Matching CAM Entries Displayed =1
so now this mac address is learned dynamically from switch port 3/3 right????????
03-25-2008 11:38 AM
It has been a while since working with catOS
I believe the sh cam dynam is showing the MAC of the attached device to that port.
03-25-2008 01:18 PM
by design, your physical interfaces on your switch will have a unique L2 mac address assigned to it. Your Logical Vlan interfaces (SVI) will share the same mac address assigned by the hardware by design.
Franco.
03-25-2008 01:24 PM
so port 3/3 will have it own unique mac address. any frame going out of that port 3/3 will originate from that mac address. for example if that port is trunk to anther switch.
while your vlans SVI will share same mac address assigned by the switch
03-25-2008 03:18 PM
thanks Francisco.
So how it is decided which Mac address is assinged to SVI interfaces.
From where that Mac address comes????
03-26-2008 03:59 AM
the switch decides that. the switch got built in mac addresses which it uses.
for example on a catalyst 6500 switch the "sh catalyst6000 chassis-mac-addresses" will give you the output below which shows that the cat 6500 got 1024 mac addresses to use for maybe STP (Spanning-tree), Vlan SVI etc.
chassis MAC addresses: 1024 addresses from 001a.e314.b000 to 001a.e314.b3ff
what is your switch model?
Franco.
03-26-2008 06:27 AM
Hi Francisco
thanks for reply
my switch model is WS-C6509 Software, Version NmpSW: 7.6(6)
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