2011-05-16
Final Exam Practice Problems.
Originally Posted By: razgriz
Just setting up a space to post questions and solutions to the final's practice problems.
'''Originally Posted By: razgriz'''
Just setting up a space to post questions and solutions to the final's practice problems.
Originally Posted By: RobertToney
Extra Credit goes to: Robert Toney, David Blausey
Problem 8.
Give an example of how the silly window syndrome can arise. Show how Nagle's algorithm prevents this situation from occurring.
The silly window syndrome arises in TCP when a server is too slow to process data and requests smaller amounts of data to be sent. If the server continues to request smaller amounts of data, the client will start sending data so small that most of the actual data being sent is IP and TCP headers, thus wasting most of the data with headers.
Nagle's Algorithm solves the problem by deciding when to wait and how long to wait.
If both the available data to send and the window size are >= than the MSS, then send the full segment
Otherwise,
If there is unconfirmed data still being sent, buffer until the ACKs arrive
else send all the data
Problem 8.
Give an example of how the silly window syndrome can arise. Show how Nagle's algorithm prevents this situation from occurring.
The silly window syndrome arises in TCP when a server is too slow to process data and requests smaller amounts of data to be sent. If the server continues to request smaller amounts of data, the client will start sending data so small that most of the actual data being sent is IP and TCP headers, thus wasting most of the data with headers.
Nagle's Algorithm solves the problem by deciding when to wait and how long to wait.
If both the available data to send and the window size are >= than the MSS, then send the full segment
Otherwise,
If there is unconfirmed data still being sent, buffer until the ACKs arrive
else send all the data
'''Originally Posted By: RobertToney'''
Extra Credit goes to: Robert Toney, David Blausey<br><br>Problem 8.<br>Give an example of how the silly window syndrome can arise. Show how Nagle's algorithm prevents this situation from occurring.<br><br>The silly window syndrome arises in TCP when a server is too slow to process data and requests smaller amounts of data to be sent. If the server continues to request smaller amounts of data, the client will start sending data so small that most of the actual data being sent is IP and TCP headers, thus wasting most of the data with headers.<br><br>Nagle's Algorithm solves the problem by deciding when to wait and how long to wait.<br>If both the available data to send and the window size are >= than the MSS, then send the full segment<br>Otherwise,<br>If there is unconfirmed data still being sent, buffer until the ACKs arrive<br>else send all the data
Originally Posted By: razgriz
4. Explain how BGP can detect and prevent loops in route paths. What are some differences between the interior and exterior BGP.
The advertised path contains a complete autonomous system (AS) path. Each node evaluates the path to see if it itself is contained within the path. If it is, then the node does not rebroadcast the path.
Interior BGP is a variant of BGP that is essentially BGP limited to the peer nodes on the same AS backbone. iBGP only advertises routes that come from outside the current AS. Exterior BGP is BGP run between AS where each AS will broadcast to the border speaker of another AS which in turn handles interdomain routing.
Group Members: Eugene Turkov, Grant Hardin
The advertised path contains a complete autonomous system (AS) path. Each node evaluates the path to see if it itself is contained within the path. If it is, then the node does not rebroadcast the path.
Interior BGP is a variant of BGP that is essentially BGP limited to the peer nodes on the same AS backbone. iBGP only advertises routes that come from outside the current AS. Exterior BGP is BGP run between AS where each AS will broadcast to the border speaker of another AS which in turn handles interdomain routing.
Group Members: Eugene Turkov, Grant Hardin
'''Originally Posted By: razgriz'''
4. Explain how BGP can detect and prevent loops in route paths. What are some differences between the interior and exterior BGP.<br><br>The advertised path contains a complete autonomous system (AS) path. Each node evaluates the path to see if it itself is contained within the path. If it is, then the node does not rebroadcast the path.<br><br>Interior BGP is a variant of BGP that is essentially BGP limited to the peer nodes on the same AS backbone. iBGP only advertises routes that come from outside the current AS. Exterior BGP is BGP run between AS where each AS will broadcast to the border speaker of another AS which in turn handles interdomain routing.<br><br>Group Members: Eugene Turkov, Grant Hardin
Originally Posted By: ahii
Problem 9:
9.Give an example of how to use iptables or ipfw.
ipfw add 1000 allow ip from 10.0.0.0/8 to any
Add this firewall rule number 1000 to allow any source from 10.0.0.0/8 to any IP address
Group members: Yun-Chieh Lin, Annie Toderici, Terri Si
9.Give an example of how to use iptables or ipfw.
ipfw add 1000 allow ip from 10.0.0.0/8 to any
Add this firewall rule number 1000 to allow any source from 10.0.0.0/8 to any IP address
Group members: Yun-Chieh Lin, Annie Toderici, Terri Si
'''Originally Posted By: ahii'''
Problem 9:<br>9.Give an example of how to use iptables or ipfw.<br>ipfw add 1000 allow ip from 10.0.0.0/8 to any<br>Add this firewall rule number 1000 to allow any source from 10.0.0.0/8 to any IP address<br>Group members: Yun-Chieh Lin, Annie Toderici, Terri Si
2011-05-22
Originally Posted By: eturkov
razgriz wrote:
4. Explain how BGP can detect and prevent loops in route paths. What are some differences between the interior and exterior BGP.
The advertised path contains a complete autonomous system (AS) path. Each node evaluates the path to see if it itself is contained within the path. If it is, then the node does not rebroadcast the path.
Interior BGP is a variant of BGP that is essentially BGP limited to the peer nodes on the same AS backbone. iBGP only advertises routes that come from outside the current AS. Exterior BGP is BGP run between AS where each AS will broadcast to the border speaker of another AS which in turn handles interdomain routing.
Group Members: Eugene Turkov, Grant Hardin
Policy:
iBGP: Within an AS, everything is nominally under the same administrative control, and thus policy issues play a much less important role in choosing routes within the AS.
eBGP: May want to control which transit traffic it forwards.
Scale:
eBGP: has to be able to deal with millions of ASs - at this level each AS is like a node.
iBGP: does not have to be quite as scalable since if there are too many nodes, we can just split a single AS into multiple ASs.
Performance:
eBGP: policy oriented - performance (OSPF, routing quality) is secondary because eBGP is a policy oriented routing scheme.
iBGP: allows iBGP routing to focus more on the level of performance realized on a route (quality of the route).
4. Explain how BGP can detect and prevent loops in route paths. What are some differences between the interior and exterior BGP.
The advertised path contains a complete autonomous system (AS) path. Each node evaluates the path to see if it itself is contained within the path. If it is, then the node does not rebroadcast the path.
Interior BGP is a variant of BGP that is essentially BGP limited to the peer nodes on the same AS backbone. iBGP only advertises routes that come from outside the current AS. Exterior BGP is BGP run between AS where each AS will broadcast to the border speaker of another AS which in turn handles interdomain routing.
Group Members: Eugene Turkov, Grant Hardin
Policy:
iBGP: Within an AS, everything is nominally under the same administrative control, and thus policy issues play a much less important role in choosing routes within the AS.
eBGP: May want to control which transit traffic it forwards.
Scale:
eBGP: has to be able to deal with millions of ASs - at this level each AS is like a node.
iBGP: does not have to be quite as scalable since if there are too many nodes, we can just split a single AS into multiple ASs.
Performance:
eBGP: policy oriented - performance (OSPF, routing quality) is secondary because eBGP is a policy oriented routing scheme.
iBGP: allows iBGP routing to focus more on the level of performance realized on a route (quality of the route).
'''Originally Posted By: eturkov'''
razgriz wrote:<br>4. Explain how BGP can detect and prevent loops in route paths. What are some differences between the interior and exterior BGP.<br><br>The advertised path contains a complete autonomous system (AS) path. Each node evaluates the path to see if it itself is contained within the path. If it is, then the node does not rebroadcast the path.<br><br>Interior BGP is a variant of BGP that is essentially BGP limited to the peer nodes on the same AS backbone. iBGP only advertises routes that come from outside the current AS. Exterior BGP is BGP run between AS where each AS will broadcast to the border speaker of another AS which in turn handles interdomain routing.<br><br>Group Members: Eugene Turkov, Grant Hardin<br><br><br>Policy:<br>iBGP: Within an AS, everything is nominally under the same administrative control, and thus policy issues play a much less important role in choosing routes within the AS.<br>eBGP: May want to control which transit traffic it forwards.<br><br>Scale:<br>eBGP: has to be able to deal with millions of ASs - at this level each AS is like a node.<br>iBGP: does not have to be quite as scalable since if there are too many nodes, we can just split a single AS into multiple ASs.<br><br>Performance:<br>eBGP: policy oriented - performance (OSPF, routing quality) is secondary because eBGP is a policy oriented routing scheme.<br>iBGP: allows iBGP routing to focus more on the level of performance realized on a route (quality of the route).
Originally Posted By: eturkov
RobertToney wrote:
Extra Credit goes to: Robert Toney, David Blausey
Problem 8.
Give an example of how the silly window syndrome can arise. Show how Nagle's algorithm prevents this situation from occurring.
The silly window syndrome arises in TCP when a server is too slow to process data and requests smaller amounts of data to be sent. If the server continues to request smaller amounts of data, the client will start sending data so small that most of the actual data being sent is IP and TCP headers, thus wasting most of the data with headers.
Nagle's Algorithm solves the problem by deciding when to wait and how long to wait.
If both the available data to send and the window size are >= than the MSS, then send the full segment
Otherwise,
If there is unconfirmed data still being sent, buffer until the ACKs arrive
else send all the data
Silly Window Syndrome
A condition that can arise in TCP in which the receiver repeatedly advertises a small window and the sender repeatedly sends a small segment to fill it. The resulting transmission of small segments makes inefficient use of network bandwidth.
Extra Credit goes to: Robert Toney, David Blausey
Problem 8.
Give an example of how the silly window syndrome can arise. Show how Nagle's algorithm prevents this situation from occurring.
The silly window syndrome arises in TCP when a server is too slow to process data and requests smaller amounts of data to be sent. If the server continues to request smaller amounts of data, the client will start sending data so small that most of the actual data being sent is IP and TCP headers, thus wasting most of the data with headers.
Nagle's Algorithm solves the problem by deciding when to wait and how long to wait.
If both the available data to send and the window size are >= than the MSS, then send the full segment
Otherwise,
If there is unconfirmed data still being sent, buffer until the ACKs arrive
else send all the data
Silly Window Syndrome
A condition that can arise in TCP in which the receiver repeatedly advertises a small window and the sender repeatedly sends a small segment to fill it. The resulting transmission of small segments makes inefficient use of network bandwidth.
'''Originally Posted By: eturkov'''
RobertToney wrote:<br>Extra Credit goes to: Robert Toney, David Blausey<br><br>Problem 8.<br>Give an example of how the silly window syndrome can arise. Show how Nagle's algorithm prevents this situation from occurring.<br><br>The silly window syndrome arises in TCP when a server is too slow to process data and requests smaller amounts of data to be sent. If the server continues to request smaller amounts of data, the client will start sending data so small that most of the actual data being sent is IP and TCP headers, thus wasting most of the data with headers.<br><br>Nagle's Algorithm solves the problem by deciding when to wait and how long to wait.<br>If both the available data to send and the window size are >= than the MSS, then send the full segment<br>Otherwise,<br>If there is unconfirmed data still being sent, buffer until the ACKs arrive<br>else send all the data<br><br><br>Silly Window Syndrome<br>A condition that can arise in TCP in which the receiver repeatedly advertises a small window and the sender repeatedly sends a small segment to fill it. The resulting transmission of small segments makes inefficient use of network bandwidth.
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