This is very important question for CCTV maintenance. A bad quality of cable or cable termination is going to create instability during lifecycle and involve otherwise avoidable efforts of stakeholders. Their maybe many school of thoughts on how cable has to be run or how it has to be terminated, but irrespective of that the outcome determines the quality not the means. And their should be a way of predicting outcomes to a fair degree, so that we can control them to a fair degree too.
Anyways, cable installation quality can be judged once a device is connected. And a rudimentary process could be using the ping layer-3 utility based on below principle and method:
(1) Generally CCTV network will be one a single LAN (VLAN). On a LAN (VLAN), routers are not involved and ARP protocol is used to determine destination host and dispatch packets
(2) Ethernet MTU is 1500 bytes typically (default) on IP cameras, switches, recorders, PCs, etc which is rarely changed by any installer. MTU means maximum frame size that is used on the Ethernet based LAN (VLAN). Jumbo frames are disabled also usually by default.
(3) If a node sends a packet of 1500 bytes, it will be fragmented into multiple frames, transmitted and reassembled at the other end.
(4) The re-assembly of the fragments is done by IP layer, but the retransmission is done by Transport layer protocol (UFP/TCP/SCTP/etc). The trick is that connection oriented protocols (TCP/SCTP) do this retransmission while connectionless transport protocols like UDP and layer-3 Protocols (like ICMP) don't. Ping has no transport layer functionality and uses raw IP packets
(5) If we send a 65500 byte ping packet from one host to another, it will be split into 44 packets based on MTU of 1500 bytes and sent as 44 frames on ethernet.
(6) If the cable or termination is faulty (which means a bad link), one or more of these frames will be lost and the IP layer entity ping will not get the ping packet, resulting in the ping client seeing a ping failure. We do this in a *closed loop [completion of one ping request-response cycle triggers next one] and immediately the faults will increase and number of ping packets sent in a given time will decrease. Our Web-Smart Switches record these as Rx/Tx Errors while there is no such statistics available on Unmanaged switches or Easy Smart switches.
(7) This observed anomaly can be used to come to an early conclusion that the cabling is not properly installed, needs checking and some rework
Health Check function of Hikvision (we use this camera brand) Bulk Configuration Tool uses ICMP (and not Transport layer UDP/TCP/etc) which means there is no retransmission of packets where an underlying ethernet fragmented frame is lost. If a fragment is lost, the ping ICMP request is deemed as dropped (or failed). This tool is used by us to determine.
A bad cable will stay bad, but a bad termination will likely degrade over time and ultimately result in a down-camera or down-AP in double quick time, That is why we seek, isolate and fix these issues upfront to avoid encountering future camera fault/downtime.
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