I have reviewed the document and in general it is quite well written and easy to read. But I found some minor issues.

In 4.1 where it describes all the fields, it generally specifies how many octets each field is, but for length it just says "Length is 8 octets". It would be good to state that the length field is 2 octets, and also format it as "Length: 2 octets ...." similar to how it is written for the other fields. Same for 4.2 and 4.3.

In 4.1 it says "The S bit SHOULD be zero upon transmission". Why is it not a MUST? When might one not set it to zero?

Apart from this I just found some minor editorial things. I'm listing them below, although I guess the RFC Editor will catch these.

Abstract:
"A MPLS" should be "An MPLS"

Section 2:
"seggregated" should be "segregated"

Section 4:
"various segments types", should be "various segment types"

Section 4.2:
"4.4is"

Section 4.3:
label.When

Section 6.3
"IPv4 /IPv6" and "[RFC7110].According"

Section 7:
"Identifiers(SIDs)" Should have space

Section 7.1:
"head end" should probably be "head-end"

Section 7.2.2:
. similarly
Node-SId

Section 8.1
SRGB.This

Section 8.2
. echo