Location 1108 - (e.g. routing switches androuters) - missing space.

Location 1192 - "This is not a secured option, it makes the 'out-of-the-box' deployment possible."  - I think this should read "Though this is not a secure option, it makes 'out-of-the-box' deployment possible."

Location 1369 - "...as it enables focused research." - I would say "...as it enables focused discovery." - but you could argue the point. Not important.

Location 1476 "...traps defined in RFC" - this should really specific the RFC number

Location 1550 "...traps defined in RFC:" - again, should refer to the specific RFC number.

Location 1568 "The user can inquire and configure..." - I wonder if this should be "enquire" ? Arguable.

Location 2332 - "Action in the outbound directionRemoves the tag..." - should be space in there between direction and Removes.

Location 2873 - "it is in CatOS..." - "It" should be capitalised.

Location 2882 - "However, this is somehow controlled ..." - should be "However, this is somewhat controlled..."

Location 2899 - "...can create VLANs on the network,. although VLAN created on a port..." - should be "...can create VLANs on the network, although a VLAN created on a port..."

Location 3636 - "(or S5820X, S500 and 'fix' switches)" - should be "(or S5820X, S500 and 'fixed' switches)

Location 3713 - "interface GigabitEthernet ½" - looks like Word Autocorrect has replaced 1/2 with the symbol

Location 3813 - "the logical number can be only 1 and 2" - should maybe be "...can be only 1 or 2" ?

Location 3946 - "The revision number must also matchso that the network...." - missing space

Location 4269 - "Be aware of there existence of MSPT pre-standard on Cisco" - should of course be "MSTP"

Location 4712 - "STP, RST, MSTP and PVST+..." - should be RSTP.

Location 5156 - Figure 6-21 caption "HP A-Series fix managed switches..." - should be "fixed"

Location 5789 - "STC cannot resolve the local loop..." - should be STP.

Location 5921 - section starting "Spanning-Tree Issues / To maintain a loop-free LAN..." - this section is a repeat of the immediately preceding lines.

Location 6137 - "...is realised by isabling STP on the interface:" - should be disabling

Location 6142 "Set port to DMI mode..." - should be MDI mode

Location 6343 "...along with advanced optionsAssumed Knowledge" - Assumed Knowledge can be removed here, as it is the next section heading

Location 6364 "...the MAC address table of switches, with virtual MAC, within the broadcast domain..." - should be "...with the virtual MAC..."

Location 6394 - "Cisco GLEP*" should be "Cisco GLBP*"

Location 7128 - "from the most basic OSPF configuration scenarios to more sophisticated, ones including redistribution" - I would remove the comma

Location 7818 "What does the routing table look like into R4 and R5?" - I would probably use "on" rather than "into"

Location 8377 - "The OSPF neighbors have many common OPSF interfaces" - should be OSPF.

Location 8601 - "...NSSA area transforms LAS Type 7" - should be "LSA"

Location 8602 - "PVST and Rapid PVST BPDU..." - this is the same as the preceding chapter. Answers don't match up with questions in this chapter.

Location 11001 - the diagram has underlined spelling mistakes. They're not actually mistakes, but whatever editing program was used should have highlighting turned off for this diagram.

Location 12021 - "Lab testing is. not necessary." - extra "." in there.