1 00:00:00,740 --> 00:00:02,940 How about BranchCache? 2 00:00:02,940 --> 00:00:06,900 The business case here for BranchCache is our users in our 3 00:00:06,900 --> 00:00:10,280 remote offices are getting timeouts attempting to access 4 00:00:10,280 --> 00:00:11,630 files from our headquarters. 5 00:00:11,630 --> 00:00:14,520 So in this case, your headquarters has your file shares, 6 00:00:14,520 --> 00:00:17,600 and you've got branch offices, and in this case, 7 00:00:17,600 --> 00:00:20,920 those branch offices maybe have lower bandwidth or 8 00:00:20,920 --> 00:00:22,890 unreliable connectivity to HQ, 9 00:00:22,890 --> 00:00:28,110 so can we cache that file share data in the remote office to give 10 00:00:28,110 --> 00:00:31,420 our users lower latency and predictable access? 11 00:00:31,420 --> 00:00:32,170 Now, honestly, 12 00:00:32,170 --> 00:00:37,800 this BranchCache case isn't as relevant now in 2022 as it was 10 years ago 13 00:00:37,800 --> 00:00:41,580 because chances are pretty good you have high‑speed connectivity in your 14 00:00:41,580 --> 00:00:45,820 remote offices, so take that for what it's worth. At any rate, let's take 15 00:00:45,820 --> 00:00:48,910 a look at the BranchCache architecture because you will be asked about 16 00:00:48,910 --> 00:00:51,180 this on your AZ‑800 exam. 17 00:00:51,180 --> 00:00:54,810 All right, so taking this topology diagram from left to right, first, 18 00:00:54,810 --> 00:00:58,570 when we install the BranchCache feature on our Windows servers, 19 00:00:58,570 --> 00:01:01,970 these servers are called content servers, and there's three 20 00:01:01,970 --> 00:01:05,770 sharing contexts, or caching contexts, for BranchCache. There's 21 00:01:05,770 --> 00:01:07,450 the file server. In my experience, 22 00:01:07,450 --> 00:01:10,700 that's the most popular one, where you have file shares that you 23 00:01:10,700 --> 00:01:13,140 want available to your branch office users. 24 00:01:13,140 --> 00:01:17,390 There's web server where you can cache web content. And then there is 25 00:01:17,390 --> 00:01:20,500 the BITS, the Background Intelligent Transfer Service, 26 00:01:20,500 --> 00:01:23,200 content server type, and that's what you would use or that's 27 00:01:23,200 --> 00:01:27,400 what you would deploy if you're using, say, Windows Server Update Services, 28 00:01:27,400 --> 00:01:31,140 WSUS, and you need to patch machines and branch offices 29 00:01:31,140 --> 00:01:33,980 and you want to cache the WSUS data. 30 00:01:33,980 --> 00:01:37,280 So those are our three contexts for BranchCache. By the way, 31 00:01:37,280 --> 00:01:41,440 besides installing the appropriate role services on your content servers, 32 00:01:41,440 --> 00:01:44,810 we can fix up the rest of the environment using Group Policy. 33 00:01:44,810 --> 00:01:46,500 I'm going to demo all this, by the way. 34 00:01:46,500 --> 00:01:49,540 I'm just going through the theory first, and then we'll do the demo. 35 00:01:49,540 --> 00:01:52,780 You need to know that there are two deployment models for BranchCache. 36 00:01:52,780 --> 00:01:55,690 One, my favorite, is the hosted cache server. 37 00:01:55,690 --> 00:01:59,200 This is where you have a Windows Server machine in the branch office 38 00:01:59,200 --> 00:02:02,550 and you've installed BranchCache on it and configured via Group Policy 39 00:02:02,550 --> 00:02:05,210 this machine to be a hosted cache server. 40 00:02:05,210 --> 00:02:09,970 Then, when you mark file shares in your content servers for caching, 41 00:02:09,970 --> 00:02:14,640 that instructs your hosted cache server to cache those particular 42 00:02:14,640 --> 00:02:18,920 shares, and then your workstation clients and other machines in that 43 00:02:18,920 --> 00:02:21,520 site have easy access to that data. 44 00:02:21,520 --> 00:02:24,790 Now when you're using BranchCache in a file server way, 45 00:02:24,790 --> 00:02:30,190 BranchCache servers need a way to mark or gauge whether a file is current. 46 00:02:30,190 --> 00:02:30,730 In other words, 47 00:02:30,730 --> 00:02:34,210 is the cached file current compared to what's on the content server? 48 00:02:34,210 --> 00:02:37,810 This is done by a process called hash generation. 49 00:02:37,810 --> 00:02:41,210 The content server and your hosted cache server will compute 50 00:02:41,210 --> 00:02:45,700 cryptographic hashes on each shared file as a way to compare 51 00:02:45,700 --> 00:02:48,460 whether the cached version is current or not. 52 00:02:48,460 --> 00:02:52,110 And again, you can do all that configuration with a Group Policy 53 00:02:52,110 --> 00:02:56,410 Object, or GPO. The other BranchCache deployment method is distributed 54 00:02:56,410 --> 00:03:01,540 cache, and this is useful when you have a distributed workforce where 55 00:03:01,540 --> 00:03:05,400 they're not attached to a single server that can serve as a hosted 56 00:03:05,400 --> 00:03:10,080 cache. With distributed cache, as the workstation clients access those 57 00:03:10,080 --> 00:03:15,160 shares, the local data in the share is cached on the client workstation 58 00:03:15,160 --> 00:03:15,860 itself. 59 00:03:15,860 --> 00:03:19,060 So Microsoft offers these options just for different business. 60 00:03:19,060 --> 00:03:23,080 Especially with the pandemic, we have more mobile workforce than we 61 00:03:23,080 --> 00:03:26,750 ever have before, so that's not to say that BranchCache is new 62 00:03:26,750 --> 00:03:28,440 because it's been in the product for many, 63 00:03:28,440 --> 00:03:36,000 many years, but there you have it. Now, as promised, let me do a demo showing you DFS and BranchCache.