Knowledge checks

An HTTP server does not remember anything about what happened during earlier steps in interacting with this HTTP client.

An HTTP client does not remember the identities of the servers with which  it has interacted.

An HTTP client does not remember anything about what happened during earlier steps in interacting with any HTTP server.

The HTTP protocol is not licensed in any country.

We say this when an HTTP server is not operational.

A cookie is used to spoof client identity to an HTTP server.

A cookies is a code used by a server, carried on a client’s HTTP request, to access information the server had earlier stored about an earlier interaction with this person. [Think about the distinction between a browser and a person.]

A cookie is a code used by a server, carried on a client’s HTTP request, to access information the server had earlier stored about an earlier interaction with this Web browser. [Think about the distinction between a browser and a person.]

A cookie is a code used by a client to authenticate a person’s identity to an HTTP server.

Like dessert, cookies are used at the end of a transaction, to indicate the end of the transaction.

The HTTP GET request message is used by a web client to post an object on a web server.

The HTTP GET request message is sent by a web server to a web client to get the next request from the web client.

The HTTP GET request message is sent by a web server to a web client to get the identity of the web client.

The HTTP GET request message is used by a web client to request a web server to send the requested object from the server to the client.

To allow a server to only send the requested object to the client if the server is not overloaded.

To allow a server to only send the requested object to the client if this object has changed since the server last sent this object to the client.

To allow a server to only send the requested object to the client if the client has never requested that object before.

To allow a server to only send the requested object to the client if the client is authorized to received that object.

1.1

2

2.1

1

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Yes, because this is a conditional GET, as evidenced by the If-Modified-Since field.

No, because a client would not request an object if it had that object in its cache.

There's not enough information in the header to answer this question.

Yes, because HTTP 1.1 is being used.

Yes, because the HTTP response indicated that only one object was requested in the HTTP GET request.

No, the server will leave the connection open as a persistent HTTP connection.

There's not enough information in the response message to answer this question.

Yes, the server will close this connection because version 1.0 of HTTP is being used, and TCP connections do not stay open persistently.

Overall, caching requires  fewer  devices/hosts to satisfy a web request, thus saving on server/cache costs.

Caching generally provides for a faster page load time at the client, if  the web cache is in the client’s institutional network, because the page is loaded from the nearby cache rather than from the distant server.

Caching allows an origin server to more carefully track which clients are requesting and receiving which web objects.

Caching uses less bandwidth coming into an institutional network where the client is located, if the cache is also located in that institutional network.

HTTP/2 has many new HTTP methods and status codes.

HTTP/2 allows objects in a persistent connection to be sent in a client-specified priority order. 

HTTP/2 allows a large object to be broken down into smaller pieces, and the transmission of those pieces to be interleaved with transmission  other smaller objects, thus preventing a large object from forcing many smaller objects to wait their turn for transmission.

HTTP/2 provides enhanced security by using transport layer security (TLS).

A checksum

A response phrase associated with a response code

A response code

The server's IP address

A sequence number

The name of the Web server (e.g., gaia.cs.umass.edu)

To allow the server to indicate to the client that it (the client) should cache this object.

To inform the HTTP cache that it (the cache) should retrieve the full object from the server, and then cache it until the specified time.

To indicate to the server that the client has cached this object from a previous GET, and the time it was cached.

To indicate to the server that the server should replace this named object with the new version of the object attached to the GET, if the object has not been modified since the specified time

To indicate to the server that the client wishes to receive this object, and the time until which it will cache the returned object in the browser's cache.

The cookie value indicates whether the user wants to use HTTP/1, HTTP/1.1, or HTTP/2 for this GET request.

The cookie value encodes the format of the reply preferred by the client in the response to this GET request.

The cookie value is an encoding of a user email address associated with the GET request.

The cookie value encodes a default set of preferences that the user has previously specified for this web site.

The cookie value itself doesn't mean anything.  It is just a value that was returned by a web server to this client during an earlier interaction.

There’s not enough information to answer this question.

No, because the client would not request an object if it were cached.

Yes, because this is a conditional GET.

Yes, because this is HTTP 1.0

No, this is a persistent connection, and so the server will keep the TCP connection open.

There’s not enough information to answer this question.