R1.What is the difference between a host and an end system? List several different types of end systems. Is a Web server an end system?
姑且认可他的答案的话,不得不说,国外的题目方式还真是别出心裁。这种句式很容易就让人先从二者存在差异出发开始论证。而他的答案是
There is no difference. Throughout this text, the words “host” and “end system” are used interchangeably. End systems include PCs, workstations, Web servers, mail servers, PDAs, Internet-connected game consoles,etc.
不过,我觉得比较奇怪的是web服务器不应该是一种服务而不是指具体的设备吗?
R4. List six access technologies. Classify each one as home access, enterprise access, or wide-area wireless access.
我不清楚这里区分的标准是什么。按照本书的目录来说,就是看主要被使用的场景,比如DSL,WIFI。然而他所给出的答案却是另一番分类:
1.Dial-up modem over telephone line: home;
2.DSL over telephone line: home or small office;
我觉得这里就有些从目前的实际情况出发的意思了。当然,ADSL对于企业来说上行速率太低,所以目前国内有SDSL的服务。
3. Cable to HFC: home;