spokoo
asked on
sh cdp neigh - info
Hello guys, i'm having some doubts that maybe you guys can help me:
magine 2 cisco devices, lets say a 6500 (on the left side) and a 2950 (on the right side)
From the left side we have 2 connections to the right side (Gi4/28 and Gi3/28)
If i make for example a "sh cdp neighbors gigabitEthernet 3/28 detail", i get:
Device ID: li02
Entry address(es):
IP address: 10.251.0.21
IP address: 10.251.0.20
Platform: cisco WS-C2950T-24, Capabilities: Switch IGMP
Interface: GigabitEthernet3/28, Port ID (outgoing port): GigabitEthernet0/1
Holdtime : 126 sec
.
.
.
If i issue the same command for the Gi4/28 i get the same thing but the outgoing por will be GigabitEthernet0/2
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The first thing i don't understand is why does it appear 2 IP addresses:
IP address: 10.251.0.21
IP address: 10.251.0.20
by the draw the 10.251.0.21 is the one connected.
--------------------------
Now if i go the the 2950 (the right side) trought the IP 10.251.0.21 and i issue the
"sh cdp neighbors gigabitEthernet 0/1 detail" or gi0/2 i get:
Device ID: 6506-0
Entry address(es):
IP address: 172.16.4.1
Platform: cisco WS-C6506, Capabilities: Router Switch IGMP
Interface: GigabitEthernet0/1, Port ID (outgoing port): GigabitEthernet3/28
Holdtime : 129 sec
which i dont understand, since the ip address i get, 172.16.4.1 is from Vlan104.
Why do i get this ip when making the sh cdp neig details for por gi0/1 and 2?
magine 2 cisco devices, lets say a 6500 (on the left side) and a 2950 (on the right side)
From the left side we have 2 connections to the right side (Gi4/28 and Gi3/28)
If i make for example a "sh cdp neighbors gigabitEthernet 3/28 detail", i get:
Device ID: li02
Entry address(es):
IP address: 10.251.0.21
IP address: 10.251.0.20
Platform: cisco WS-C2950T-24, Capabilities: Switch IGMP
Interface: GigabitEthernet3/28, Port ID (outgoing port): GigabitEthernet0/1
Holdtime : 126 sec
.
.
.
If i issue the same command for the Gi4/28 i get the same thing but the outgoing por will be GigabitEthernet0/2
---------------------
The first thing i don't understand is why does it appear 2 IP addresses:
IP address: 10.251.0.21
IP address: 10.251.0.20
by the draw the 10.251.0.21 is the one connected.
--------------------------
Now if i go the the 2950 (the right side) trought the IP 10.251.0.21 and i issue the
"sh cdp neighbors gigabitEthernet 0/1 detail" or gi0/2 i get:
Device ID: 6506-0
Entry address(es):
IP address: 172.16.4.1
Platform: cisco WS-C6506, Capabilities: Router Switch IGMP
Interface: GigabitEthernet0/1, Port ID (outgoing port): GigabitEthernet3/28
Holdtime : 129 sec
which i dont understand, since the ip address i get, 172.16.4.1 is from Vlan104.
Why do i get this ip when making the sh cdp neig details for por gi0/1 and 2?
ASKER CERTIFIED SOLUTION
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ASKER
Hello All!
The Vlan 104 is configured in the following way:
interface Vlan104
ip address 172.16.4.1 255.255.255.0
and the for example, the interface gi3/28:
interface GigabitEthernet3/28
no ip address
switchport
switchport access vlan 10
switchport mode trunk
switchport nonegotiate
The Vlan 104 is configured in the following way:
interface Vlan104
ip address 172.16.4.1 255.255.255.0
and the for example, the interface gi3/28:
interface GigabitEthernet3/28
no ip address
switchport
switchport access vlan 10
switchport mode trunk
switchport nonegotiate
The asker has requested for
Why do i get this ip when making the sh cdp neig details for por gi0/1 and 2?
Answer provided is
GigabitEthernet3/28 must be associated to Vlan-104 on the other router.
As Gig 3/48 is a layer-2 interface, sh cdp nei will show the IP address of the vlan for which the interface is associated with.
He can tell why he won't accept the answer. Is there anything else he wants to know apart from where the IP address is being fetched?
Why do i get this ip when making the sh cdp neig details for por gi0/1 and 2?
Answer provided is
GigabitEthernet3/28 must be associated to Vlan-104 on the other router.
As Gig 3/48 is a layer-2 interface, sh cdp nei will show the IP address of the vlan for which the interface is associated with.
He can tell why he won't accept the answer. Is there anything else he wants to know apart from where the IP address is being fetched?
What rubbish answer is this ...
Is VLAN 104 is your management VLAN? Are these ports member of some vlan. Detailed configuration will give better picture.
nayan