Questions tagged [errors]

For questions about interface errors on a network device. For instance, you have an interface with a lot of input errors, but you don't know how to troubleshoot it.

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Troubleshooting network issues; General inquiry

I work as a junior network admin at an ISP and I would like your help in resolving an issue whose cause is not readily apparent. Rn I am trying to troubleshoot a case where a switch interface randomly ...
Giorgos Amoiridis's user avatar
2 votes
2 answers
155 views

In determining the Hamming distance, how does one know what the list of valid codewords are?

Hamming distance is said to be the number of bits that differ between two codewords. If two code words differ by a distance of d, then up to d-1 bit flips can be detected. The example given for such ...
penguin99's user avatar
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1 answer
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Why I’m getting overlaps with fast Ethernet 0/1 when assigning an ip

But I have been receiving error code when I want to assist an ip to s1/0
Ebuka Dike's user avatar
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0 answers
32 views

panic:integer divide fault Message Observed on SRX 5800 Routine Engine

We are running 2 x Juniper SRX 5800 Firewalls in a cluster environment. Node 0 got rebooted and Node 1 took over the master role. Node 0 came back online after reboot. The reasons for Node 0 to reboot ...
Nabeel's user avatar
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3 answers
3k views

Cannot create subinterface

I'm trying to connect 4 networks with 1 router, i created 2 sub-interfaces in the router, when i tried to create the 3rd sub-interface i got this output "%Cannot create sub-interface", this ...
Muath's user avatar
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1 vote
3 answers
683 views

CRC errors in DC, ruled out L1 issues

I have a very strange problem with links in one datacenter and I'm looking for some other solutions I haven't looked for yet. We have a network based on Cisco Nexus 3K and most of the core links ...
Sage's user avatar
  • 21
2 votes
1 answer
467 views

How does the Ethernet handles start of frame collision?

The Ethernet preamble, 56 bits of alternating 1 and 0 bits, allowing the receiver to synchronize its clock to the transmitter, followed by a one-octet start frame delimiter byte (10101011) and then ...
Leandro Moreira's user avatar
1 vote
2 answers
5k views

Cisco nexus CRC error on interface

I have dual stack vPC setup between 4 cisco nexus switch as per above design. I have noticed recently that getting CRC error on cisco 3064 all 4 interface connected to N9K, and during peak traffic ...
Satish's user avatar
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1 answer
7k views

JunOS: FPC Major error alarm

I hope everyone is doing fine! This morning I've run into a problem. My uplink interface went down for unknown reasons. Upon checking system alarms I see this: show system alarms 1 alarms currently ...
Nenq's user avatar
  • 45
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0 answers
782 views

Cisco Time-Domain Reflectometer (TDR) returns cable length of 65535 meters?

Something very strange here. Today I noticed a device was unreachable. Giving a look at the switch it connects to (Cisco 3750, version 12.2(35)SE5), the port was in err-disabled due to link-flap: #sh ...
kuma's user avatar
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1 answer
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CRC R bit size to guarantee error free

For a Link Layer frame, it's common to include some bits for redundancy. Suppose we have a frame with X bits of actual data, and want Y bits of error-correction bits. What size do we need to choose ...
rahul chawla's user avatar
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What is wrong with this CRC calculation? [duplicate]

I have gone through a few documents to understand how to check that an ethernet frame is valid. I do the following calculation, but I can see it is incorrect because it does not result in a crc value ...
DevShark's user avatar
  • 175
3 votes
1 answer
1k views

Resource Errors on 1G interfaces in Juniper router

We are observing resource errors on almost many 1G links on Juniper MX240. The resource errors counter is quite high. The MPC type is MPC Type 1 3D. I am sharing the output of command 'show interface ...
Nabeel's user avatar
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1 vote
1 answer
312 views

Intermittent issues on a dark fibre point to point link

After a bit of advice on an intermittent issue i'm investigating. We have two buildings on the same site connected by 548m fibre run that we own and it was installed around 10 years ago. Over the ...
JLS's user avatar
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2 votes
1 answer
904 views

Layer 2 error correction

How are acknowledgement sent at data link layer to the sender when crc of frame is incorrect?
Ajay Pandita's user avatar
1 vote
1 answer
2k views

User Datagram Protocol (UDP) protocol can error control?

UDP can congestion control? UDP can flow control? UDP have some error correction mechanism?
Manjitha Teshara's user avatar
0 votes
1 answer
604 views

Layer 2 ARQ protocols

Some authors (i.e. Tanenbaum, Stallings) reference ARQ protocols as layer 2 mechanisms for handling errors. Even this page from Wikipedia says that these protocols reside in the Data Link or ...
T.G.'s user avatar
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2 votes
1 answer
64 views

How often does it happen that at the Layer 2 (MAC) an error goes undetected?

I know there are certain error detecting and correcting codes added at the Layer 2. However is it still possible to have errors go undetected eve with the addition of these codes? What type of ...
yoyo_fun's user avatar
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5 votes
1 answer
2k views

Physical layer errors in Ethernet

What happens if an error is detected at the lowest possible layer of the stack ISO/OSI for Ethernet? For example, considering 100BASE-TX, it is implemented with a 4B5B coding this means that there ...
ocirocir's user avatar
  • 153
2 votes
2 answers
3k views

cisco Total output drops on interface

we have c3850 trunk with other switch 4948 and its LACP 4x1G interface bonding (etherchannel) out of 4 1G we are getting Total output drops on 2 interface. This is all started yesterday when i ...
Satish's user avatar
  • 4,369
2 votes
4 answers
2k views

Why are there error detection methods in almost every layer of a network?

What is the purpose of checking errors in almost every layer of a network? For example, I don't see the purpose of using a checksum in TCP given that CRC has already been checked in lower layers. Or ...
Carlos Pinzón's user avatar
0 votes
1 answer
4k views

Underruns in ASA interface

I have an ASA firewall in production. When I issue the show interface command, there are lots of underruns and it keeps increasing. I have change the LAN cable, reset the interface, enable and disable ...
Oyin's user avatar
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5 votes
1 answer
813 views

In Cyclic Redundancy Check, how does the receiver knows what the generator polynomial is?

Must the receiver know the generator polynomial in order to detect the errors in the received data? So how does it know what generator polynomial the sender has used?
Romy's user avatar
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1 vote
1 answer
473 views

How can I test my ping application for proper detection of ICMP return types and codes [closed]

I have developed an application that partially replicates the functionality of the builtin ping application, essentially sending an ICMP packet, receiving the response, and parsing the header. ...
MDMoore313's user avatar
4 votes
3 answers
2k views

What is "collision domain"

In Tanenbaum's Computer Networks: What happens if more than one of the stations or ports wants to send a frame at the same time? Again, switches differ from hubs. In a hub, all stations are in ...
Tim's user avatar
  • 1,545
1 vote
3 answers
466 views

All tunnels down on Cisco 7204VXR with debug message "Unable to generate DH phase 2 parameters!"

I have 40 or 50 tunnels with over 200 SAs active on a 7204VXR with NPE-G1 using the software crypto engine (no VAS card installed). The working config was transferred over from a 2821 with AIM-VPN ...
Guy Thouret's user avatar
6 votes
2 answers
2k views

ASA VPN communication issue

I have got an issue where SPOKE 1 and SPOKE 2 cannot communicate with each other. However, SPOKE 1 and SPOKE 2 can communicate with HUB. Please see configuration below for spoke and hub. SPOKE 1 (...
Rohit Mangotra's user avatar
4 votes
2 answers
736 views

Multiple error types Cisco 861 router

I have a connection that users complain is really slow at times. My SNMP graphs from Observium don't show the bandwidth being fully used or high latency. They show a lot of errors on the WAN port of ...
PHLiGHT's user avatar
  • 175
6 votes
1 answer
682 views

Juniper MX-5 EOPE Drop Pkt Cnt Incrementing

When running show pfe statistics error on a a couple of MX platforms, I see the EOPE Drop Pkt Cnt counter incrementing on 6 MX's out of 22. I believe these are "End-Of-Packet errors", but can't find ...
DrBru's user avatar
  • 1,619
2 votes
1 answer
1k views

Why am I having issues accessing a website hosted on servers behind a load-balancer?

I am having an issue with an offsite location accessing a website that is hosted on 3 servers behind a Coyotoepoint Load-Balancer, at our Corporate Office. We currently have well over 500 locations ...
Luke's user avatar
  • 114
10 votes
2 answers
2k views

Cisco 7604 + RSP720 3CXL + WS-X6704-10GE increasing the error counters on the port, but there is no loss through the port

Cisco 7604 + RSP720 3CXL + WS-X6704-10GE increasing the error counters on the port, but there is no loss through the port: #sh interfaces Te3/4 TenGigabitEthernet3/4 is up, line protocol is up (...
Allan Sundry's user avatar
4 votes
1 answer
2k views

CRC & Align Errors on D-Link switch, network down

I have network topology: (room 3) D-Link DES-1024D | | (room 2 MAIN) (room 4) Baseline 3COM Switch 2948-...
antongrt's user avatar
6 votes
2 answers
2k views

Cisco 7609-S Line card error counter is regularly exceeding threshold

I am receiving the following syslog messages on a 7609-S. Jun 17 11:52:27.560 BST: %CONST_DIAG-SP-4-ERROR_COUNTER_DATA: ID:47 IN:4 PO:255 RE:169 RM:255 DV:5 EG:2 CF:10 TF:472 Jun 17 11:52:27.560 BST: ...
Baldrick's user avatar
  • 5,290
4 votes
4 answers
2k views

Cisco 2600 series router logging a lot of "Memory allocation failed" errors

We are getting the below two error messages randomly on a 2600 series router. Syslog shows the router has been fine up until a few days ago. Would a reboot most likely cure the issue or is it most ...
Adam Loveless's user avatar