RFC 791, "Internet Protocol", September 1981

Errata ID: 5038
Status: Rejected
Type: Technical
Publication Format(s) : TEXT
Reported By: Prabhu K Lokesh
Date Reported: 2017-06-10
Rejected by: Suresh Krishnan
Date Rejected: 2020-03-25

Section 3.1 says:

The option begins with the option type code.  The second octet
        is the option length which includes the option type code and the
        length octet, the pointer octet, and length-3 octets of route
        data.

It should say:

The option begins with the option type code.  The second octet
        is the option length, measured in octets, including the option 
        type code octet, the length octet, the pointer octet, and the
        octets of route data.

Notes:

The way the second octet is defined, although readable to majority of the audience with no concern, will incorrectly equate to:
length = 'option type code octet' + 'length octet + 'pointer octet' + length - 3 octet of route data

So, what is the value of 'length' in 'length - 3'; when reader encounters 'length - 3', the term 'length' itself is not completely defined. Using the term 'length - 3' to define the term 'length' may not be very appropriate.

For better readability, we can simply write -
The second octet is the option length, measured in octets, including the option type code octet, the length octet, the pointer octet, and the octets of route data.

The same correction applies to the following sections -
3.1. Internet Header Format > Loose Source and Record Route
3.1. Internet Header Format > Strict Source and Record Route
3.1. Internet Header Format > Record Route
--VERIFIER NOTES--
While the text can be simplified as the submitter of the Erratum implies, the current text has been in use for close to 4 decades without any interoperability issues rising out of it. Hence this

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