I am having error "CrcAlign-Err" on WS-C4948 port

[nesrin]

I am working on WS-C4948 and I have notice that when I run *sh interface ... I am having the following error

#sh interface gigabitEthernet 1/48
GigabitEthernet1/48 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet Port, address is 0017.......f (bia 0017.e0cf.c9ef)
Description: xgee14-rtp-1-Eth1/6
MTU 9198 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX
Media-type configured as SFP connector
input flow-control is off, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:02, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 159000 bits/sec, 112 packets/sec
5 minute output rate 847000 bits/sec, 135 packets/sec
4102846468 packets input, 665901476622 bytes, 0 no buffer
Received 2038661342 broadcasts (649455830 multicasts)
2 runts, 0 giants, 0 throttles
154345 input errors, 154343 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
3536444978 packets output, 2341310271333 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

.............................................

I have also ran the following command

*sh int gigabitEthernet 1/48 coun errors

Port CrcAlign-Err Dropped-Bad-Pkts Collisions Symbol-Err
Gi1/48 154343 0 0 0

Port Undersize Oversize Fragments Jabbers
Gi1/48 0 0 2 0

Port Single-Col Multi-Col Late-Col Excess-Col
Gi1/48 0 0 0 0

Port Deferred-Col False-Car Carri-Sen Sequence-Err
Gi1/48 0 0 0 0

So my question is

1) I limited the allowed vlan from all to allowing certain VLANs but Broadcast did not change.

2)when I can say that I have high broadcast? and how can I reduce it?

3)how can I fix the above error (CrcAlign-Err )? I have different MTU on both side the specified port is connected to Nexus 5596 do you think that would cause the error or both ports will negotiate ?

Thank you

[Upgrading_To_CheckPoint!]

Bad patch cable.

[acampbell]

Hi,
Totally agree with WhiskeySixRadio +5

Exam fibre connections in the path and clean them.
Re-test

[nesrin]

Thank you for the quick reply. how about the following questions:

1) I limited the allowed vlan from (switchport allow all) to (switchport allow vlan .....certain VLANs) but Broadcast number  did not change. why?

2)when I can say that I have high broadcast? and how can I reduce it?

[Mark Malone · Accepted solution]

1) I limited the allowed vlan from (switchport allow all) to (switchport allow vlan .....certain VLANs) but Broadcast number did not change. why?

before you can answer that you need to understand where the broadcasts are coming from , are they legitimate what vlan etc , use wireshark , a bad NIC can constantly flood them out . Limiting vlans doesn't mean you have stopped broadcasts or prevented them , they could be mostly coming from 1 vlan , you dont know until you investigate it

2)when I can say that I have high broadcast? and how can I reduce it?
Again this his can depend multiple things , how big the vlan is how many hosts etc are on it ,what type of application traffic is being sent across the network , could be broadcast or multicast , could be NIC issues

read this for some ideas
https://searchnetworking.techtarget.com/answer/How-can-I-reduce-the-number-of-broadcasts-on-my-network

[nesrin]

Thank you Mark for the explanation and the link. I don't know how to use Wireshark but I have to learn it.

[Leo Laohoo]

CRC = Layer 1 issue.
1. Replace the optics of both sides;
If problem still occurs,
2. Replace the patch cable of both sides

[nesrin]

Thank you All and I really appreciate your help.