02-16-2023 05:53 AM
I connected a computer with a 25G interface in Cisco Catalyst 9500-48Y4C switch. I saw ports on both PC and the switch are UP (green light). However, the switch could not learn the computer's MAC address. Also, the computer did not know the MAC address of the connected switch port. It seems to be a layer-2 problem. When I tried the ping from the computer to the switch port, as the MAC address of the switch port is not listed on the computer, the broadcast messages were sent out. But what surprised me is that switch still received the broadcast messages from the computer. What is the problem here?
-------------On the switch---------------------
show interface TwentyFiveGigE1/0/X
TwentyFiveGigE1/0/X is up, line protocol is up (connected)
Hardware is Twenty Five Gigabit Ethernet, address is 8024.8f2f.451f (bia 8024.8f2f.451f)
Internet address is 123.123.123.123/24
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10Gb/s, link type is auto, media type is SFP-10GBase-CU3M
input flow-control is on, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:00, output hang never
Last clearing of "show interface" counters 1w2d
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
3052 packets input, 201865 bytes, 0 no buffer
Received 3052 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 235 multicast, 0 pause input
0 input packets with dribble condition detected
500755 packets output, 45412032 bytes, 0 underruns
Output 2 broadcasts (0 IP multicasts)
0 output errors, 0 collisions, 6 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
When I ran "ping 123.123.123.123" from the computer, the switch port updated broadcast messages:
show interface TwentyFiveGigE1/0/X
TwentyFiveGigE1/0/X is up, line protocol is up (connected)
Hardware is Twenty Five Gigabit Ethernet, address is 8024.8f2f.451f (bia 8024.8f2f.451f)
Internet address is 123.123.123.123/24
MTU 1500 bytes, BW 10000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 10Gb/s, link type is auto, media type is SFP-10GBase-CU3M
input flow-control is on, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:02, output hang never
Last clearing of "show interface" counters 1w2d
Input queue: 0/375/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
3058 packets input, 202249 bytes, 0 no buffer
Received 3058 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 235 multicast, 0 pause input
0 input packets with dribble condition detected
500773 packets output, 45415012 bytes, 0 underruns
Output 2 broadcasts (0 IP multicasts)
0 output errors, 0 collisions, 6 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
Switch did not learn MAC address at all:
show mac address-table interface TwentyFiveGigE1/0/X
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
Other information on the switch:
Cisco IOS XE Software, Version 17.03.04
show vlan
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Twe1/0/1, Twe1/0/2, Twe1/0/3
Twe1/0/4, Twe1/0/5, Twe1/0/6
Twe1/0/7, Twe1/0/8, Twe1/0/9
Twe1/0/10, Twe1/0/11, Twe1/0/12
Twe1/0/13, Twe1/0/14, Twe1/0/15
Twe1/0/16, Twe1/0/17, Twe1/0/18
Twe1/0/19, Twe1/0/20, Twe1/0/21
Twe1/0/22, Twe1/0/23, Twe1/0/24
Twe1/0/25, Twe1/0/26, Twe1/0/27
Twe1/0/28, Twe1/0/29, Twe1/0/30
Twe1/0/31, Twe1/0/32, Twe1/0/33
Twe1/0/34, Twe1/0/35, Twe1/0/36
Twe1/0/37, Twe1/0/38, Twe1/0/39
Twe1/0/40, Twe1/0/41, Twe1/0/42
Twe1/0/43, Twe1/0/44, Twe1/0/45
Twe1/0/46, Twe1/0/47, Hu1/0/50
Hu1/0/51, Hu1/0/52
2 VLAN0002 active
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup
--------------On the computer--------------------------
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 123.123.123.1 netmask 255.255.255.0 broadcast 123.123.123.255
ether 90:e2:ba:e2:76:cc txqueuelen 1000 (Ethernet)
RX packets 1894 bytes 266637 (266.6 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 6387 bytes 300306 (300.3 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
user@PC:~$ arp
Address HWtype HWaddress Flags Mask Iface
123.123.123.123 (incomplete) enp2s0f0
02-16-2023 06:08 AM
Does the computer support 10GB connection
as per your output, other computers show only 1000(ethernet) ?
if the PC supports 10GB, then try hard coding to 10GB speed and also no auto-negotiation and check.
02-16-2023 06:19 AM
are you use vlan 2 for this PC ??
02-16-2023 01:50 PM
Loop the port of the optic and see if the port goes up/up.
Do the same to the server with 25 Gbps optics. I suspect the NIC card of the server is dead or not configured properly.
02-27-2023 03:54 AM
@balaji.bandi Yes, I used 10Gbps Intel NIC for two computers.
@MHM Cisco World VLAN 2 is empty.
show vlan id 2
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
2 VLAN0002 active
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
2 enet 100002 1500 - - - - - 0 0
Remote SPAN VLAN
----------------
Disabled
Primary Secondary Type Ports
------- --------- ----------------- ------------------------------------------
show vlan id 1
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Twe1/0/1, Twe1/0/2, Twe1/0/3
Twe1/0/4, Twe1/0/5, Twe1/0/6
Twe1/0/7, Twe1/0/8, Twe1/0/9
Twe1/0/10, Twe1/0/11, Twe1/0/12
Twe1/0/13, Twe1/0/14, Twe1/0/15
Twe1/0/16, Twe1/0/17, Twe1/0/18
Twe1/0/19, Twe1/0/20, Twe1/0/21
Twe1/0/22, Twe1/0/23, Twe1/0/24
Twe1/0/25, Twe1/0/26, Twe1/0/27
Twe1/0/28, Twe1/0/29, Twe1/0/30
Twe1/0/31, Twe1/0/32, Twe1/0/33
Twe1/0/34, Twe1/0/35, Twe1/0/36
Twe1/0/37, Twe1/0/38, Twe1/0/39
Twe1/0/40, Twe1/0/41, Twe1/0/42
Twe1/0/43, Twe1/0/44, Twe1/0/45
Twe1/0/46, Twe1/0/47, Twe1/0/48
Hu1/0/50, Hu1/0/51, Hu1/0/52
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1 enet 100001 1500 - - - - - 0 0
Remote SPAN VLAN
----------------
Disabled
Primary Secondary Type Ports
------- --------- ----------------- ------------------------------------------
@Leo Laohoo Loop test for switch ports (one cable connecting directly 2 switch ports) and for the computers' interfaces (one cable directly connecting two PCs with 10Gbps NIC) is working well. The status is up/up for both cases.
When I performed loop test for the computers, I could ping two PCs with each other. Therefore, I believe that there should not be a problem with NICs.
Please let me know how to further investigate the issue. Thanks a lot!
02-27-2023 05:19 AM
you dont answer me are you use VLAN2 for both PC !!
03-01-2023 04:51 PM
do you have any other device to test it? (rather rely on only device may have issue ?)
03-02-2023 01:03 AM
@balaji.bandi Do you mean PCs? I have some other PCs. But the issue still remains.
03-02-2023 01:48 AM
what NIC card PC has ? has this cable compatible-SFP-10GBase-CU3M ?
03-02-2023 02:13 AM - edited 03-02-2023 02:20 AM
@balaji.bandi This is Intel NIC spec: https://www.intel.com/content/www/us/en/products/sku/41282/intel-82599es-10-gigabit-ethernet-controller/specifications.html?wapkw=Intel%20Corporation%2082599ES%2010-Gigabit
Two PCs could ping each other using the same cable (directly without the switch in between). Therefore, I do not think it is the NIC issue.
03-02-2023 02:53 AM
have you tried :
interface TwentyFiveGigE1/0/X
switchport nonegotiate
03-02-2023 03:23 AM
@balaji.bandi I ran the cmd you suggested on both switch ports connected to the PCs, but still no luck. PCs could not ping each other.
conf t
interface TwentyFiveGigE1/0/X
switchport nonegotiate
03-02-2023 03:53 AM
can you post after that command added
show interface tw 1/0/X
show IP arp
show mac address interface tw 1/0/x
02-27-2023 05:53 AM
Hi @MHM Cisco World No, I dont use VLAN2 for two PCs. The PCs all belong to VLAN1 as default.
02-27-2023 08:15 AM
both PC is share same subnet and the SW must bridge the frames,
but I see IP assign to port !! i.e. this port now is L3 not L2 and that why the ping is failed
show interface TwentyFiveGigE1/0/X
TwentyFiveGigE1/0/X is up, line protocol is up (connected)
Internet address is 123.123.123.123/24 <<- this done by no switchport and assign IP
what you want switchport access vlan 1 in both port connect to PC, and remove the IP
and assign IP to both PC and sure the ping will success
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