SNMP - Decode Hex String Value - snmp

Question

This is my first question here, so hope it's correctly done.
Im trying to get some information from a ZTE C300 OLT.
The thing is when i try to get the SN of one of the ONTS I get the response in HEX-String
snmpwalk -cpublic -v2c [OLTIP] 1.3.6.1.4.1.3902.1082.500.10.2.2.5.1.2
And this is the response that I get
SNMPv2-SMI::enterprises.3902.1082.500.10.2.2.5.1.2.285278736.1 = Hex-STRING: 5A 54 45 47 C8 79 9B 27
This is the SN that i have on the OLT ZTEGC8799B27, but im trying to convert the HEX-STRING into text and i don't get that SN text.
Indeed i have a python script for SNMP and the response that i get for that OID is
{'1.3.6.1.4.1.3902.1082.500.10.2.2.5.1.2.285278736.1': "ZTEGÈy\x9b'"}
Can someone give me a hand on this?. I'm new on SNMP and this is giving me some headache.
Thanks in advace!

Answer 1

This is a 8 octet hex string, the first 4 octets are ASCII.
Just convert hex 2 ascii.

Answer 2

Indeed it was easier. The firts 4 bytes were encoded, and the other 4 is the actual serial number splitted every 2 digits. So i only need to decode the first part and concatenate the rest.

Answer 3

Works with OLT ZTE C320
def hex_str(str):
str = str.strip()
str = str.split(' ')
vendor_id = ''
serial = str[4:]
serial = "".join(serial)
for hex_byte in str[:4]:
vendor_id += chr(int(hex_byte, 16))
normalized_serial = vendor_id + serial
return normalized_serial
def ascii_to_hex(str):
arr = []
hex_byte = ''
for i in range(len(str)):
hex_byte += hex(ord(str[i]))
hex_byte = hex_byte.replace('0x', ' ')
hex_byte = hex_str(hex_byte)
return hex_byte
# value = f"5A 54 45 47 C8 79 9B 27 "
# value = f"49 54 42 53 8B 69 A2 45 "
# value = f"ZTEGÈy\x9b'"
value = f"ITBS2Lz/"
# value = f"ITBS2HP#"
if(len(value) == 24):
print(hex_str(value))
else:
print(ascii_to_hex(value))