"Shop" is a way to refer to the place where you work, or where a specific type of work is carried out. Refer to these definitions (from Oxford Dictionaries):
2 [usually with modifier] A place where things are manufactured or
repaired; a workshop:
"an auto repair shop"
2.1 A room or department in a factory where a particular stage of
production is carried out:
"the machine shop"
2.2 (the shop) informal The place where one works:
"she pointed to the classroom ceiling—'I live here, over the shop.'"
By extension, "shop" can be used as a metonym for the company itself, or a department of the company that is based in the place that is the "shop."
Cisco is a company that makes networking and telecoms equipment.
As @TRomano says, the all-(sth.) pattern is used to indicate that (sth.) is used exclusively, or that the thing being talked about is completely (sth.). It doesn't necessarily apply just to equipment, but can also apply to characteristics such as colour, gender/sex, and others:
As @TRomano also says, the all-(sth.) pattern isn't required. The all part can be omitted, and the meaning will be retained. However, including the all part emphasizes the fact that (sth.) is used exclusively.
[Walt Disney World] was an all Cisco shop when it came to routers and
What is the speaker is saying, then, is that Walt Disney World exclusively used equipment manufactured by Cisco. The phrase when it came to — — limits the equipment the speaker includes in the statement to just routers and network switches.
If the when it came to — — phrase wasn't used, you'd be free to assume that all networking equipment (not just routers and switches) was manufactured by Cisco, which might include networked telephones or wireless access points as well.