What literature or articles to read to understand what basic IT infrastructure should a modern small business have?

Question

System administration

In order not to just pay + - a million for an IT audit for the further development of the IT infrastructure and architecture for the interaction of software and equipment in an office of 50 people, please advise literature or full articles describing what technologies are commonly used for the office of a modern company with a description and, preferably, examples, some introductory course. A basic understanding is required before ordering an audit.
For example, description and examples:

• providing a reliable Internet access channel,
  
• wireless Wi-Fi networks,
  
• video conferencing systems in meeting rooms,
  
• systems and means of information security,
  
• IP telephony, PBX, VATS,
  
• corporate email,
  
• ensuring storage, backup and security of corporate data,
  
• access to corporate resources, differentiation of rights, virtualization
  
• and etc.
  

Answer 1

hire a normal system administrator, he will tell you based on the needs of your company specifically.
In general, the tasks listed are the usual standard set.
What can be audited there for just 50 users?

Answer 2

Globally, the question is identical to "what should I read to become a therapist, learn how to drive a KAMAZ, and also perform at the stadium with a rock concert."

All these professions and administration have one thing in common - real practice is needed to master them. Because most of the work is solving problems and fighting the imperfection of the world (which differs sharply from the ideal one described in books).
Literature and articles will never replace the practice of solving user and infrastructure problems, and all the baggage of theoretical knowledge will only make it difficult to communicate with people who have had such a practice. Because every second statement, either on your side or on the other side of the dialog, will trigger WTF.
For example, the textbook says that the CISCO hardware supports h323. And the Panasonic hardware also supports h323. After reading the textbook, you will be strongly convinced that one can be combined with another and get a profit. In fact, it turns out that one does not understand the other in any way, but if you put Asterisk between these two idiots, understanding is achieved instantly.
Consequently, the only way to communicate with engineers in the same language and on the same wavelength is to independently build (and break) such an infrastructure several times, for which you need to go to an enterprise where such infrastructure exists.
Therefore, you should either hire a consultant whom you will trust and who will translate from engineering into human language, or literally, master the profession of an administrator after at least 3-6 months of internship.

Answer 3

If you are normally friends with English, then go to cisco.com
there are a bunch of diagrams for all typical cases.
The same is true for other vendors.

Answer 4

It's not solved that way. There is a set of practices described in ITIL, you can read it. You need to start by creating a service catalog. Examples are easy to google, for example here . Further, it is planned what kind of infrastructure is needed for this (premises, communication network, electricity, workstations, peripheral equipment, servers, software). Further, ITSM (service desk) is wound up on this, then accounting for the CMDB type, requirements for a typical workstation, and then a continuous optimization process.

Answer 5

normal admin != normal IBshnik or a person who is responsible for business continuity.!
But really, the admin will give you a base (foundation) on which you can put everything else.
The main thing is to understand whether all this is necessary for the business so that it does not turn out that the cost of the entire solution is several times higher than the cost of the business itself)

Answer 6

There is no standard for what you describe. Everything that you described is selected for each task EXCLUSIVELY individually.
Auditors cost so much for a reason, because they sell the knowledge / experience and skills accumulated over the years / decades. And not every auditor / analyst / expert will be able and will understand all this at once.
And it also takes time to analyze it all, come up with all the options, calculate them and calculate the effectiveness in order to make a rational decision.
providing a reliable Internet access channel - each solution has its own reliability criterion: someone needs an SLA from a provider about no more than 4 hours of downtime per year, someone needs 7 backup channels - the amounts spent and types of solution will differ hundreds of times.
wireless Wi-Fi networks - again: this is just a point for the director's mobile phone or a reliable seamless coverage of the entire warehouse / workshop / site. In the second case, without radio frequency management and analysis on a specific area, it is impossible to say anything. Deploy a typical solution, and you will have wild tips from which it will go down.
video conferencing systems in meeting rooms - there are so many of them that a dime a dozen: someone needs a TV with a webcam and Skype / zoom, someone needs a ciscophone with HD porting the entire room, an uninterrupted signal that never logged for a second, and a connection to the interlocutor according to GOST VPN - the price of the solution is natural: from TV to Boeing.
information security systems and tools - the main thing is that the cost of information security does not exceed the cost of protected information and does not greatly interfere with working with it, and then a dime a dozen.
IP-telephony, PBX, VATS - here again what kind of organization and what this telephony will be used for. If you call the warehouse for an accountant, ask for the balance - this is one thing. if there is a completely different call center, and also in this case all sorts of integrations with CMS and third-party
corporate email services - whatever marketing, security, admins, directors wish. from typical mailboxes "department" - "company"@gmail.com, buying paid cloud services with attaching your domain, to an extra with storing data on a sealed storage in your own server room under double protection.
ensuring storage, backup and security of corporate data - what to store? how to copy? from documents in a shared folder of booze, to a petabyte data factory in a media studio with 40G links to designers' computers - for all your needs.
access to corporate resources, differentiation of rights, virtualization - again, everything depends on resources and what they want to do with them - someone needs Google docs, someone needs VPNs