[ppsp] WGLC comments draft-ietf-ppsp-problem-statement-03

[Martin Stiemerling <[e-mail]>]

[Writing not as WG chair, but as individual contributor]

Dear all,

I have reviewed the draft draft-ietf-ppsp-problem-statement-03 and did mainly find editorial issues. 

Non-Editorials:
- Section 3.1, 2nd paragraph, "  With PPSP, P2P cache can detect P2P streaming applications much  easier without needing to update its library."; It might not be completely  obvious to an average reader why a standarizded P2P protocol would make things easier here. How about adding at the end of this sentence: ", as there is only a single protocol to be detected and not a potentially unknown set of proprietary P2P protocols". 
- Section 3.2, 1st paragraph, 1st sentence. I cannot see the relationship between the section's intended scope and DONA or any other content centric networking. 
- Section 3.2, 3rd paragraph, You lost me with the everything after the first sentence of this paragraph. I don't understand what it is saying or what it should be saying. 
- Section 3.3, 1st paragraph, The first sentence about "mobility and wireless are becoming increasingly dominate " is basically reflecting the current situation, but what is the relationship to the future Internet activities mentioned there? The mobile and wireless part is already sort of dominant by today.
- Section 3.4, 2nd paragraph: I know what this paragraph is aiming at, i.e., reusing the same library and potentially other optimizations. But it would be better to rephrase the paragraph. E.g., "PPSP can help to reduce the resource consumption on resource constraint devices, such as STBs or mobile phones, by reusing a PPSP base library and ..."

- Security section: 
I'm not sure that the current security section is exactly what we need for the problem statement. It is on one hand detailed on the threat description (e.g., "peers may report fake information about available content"), but on the other side lacks the description of countermeasures to those threats. 
I would propose to rewrite the security section to cover a broader focus on highlighting certain threats, but letting the fix to those to the particular protocol specifications, i.e., the peer protocol and the tracker protocol.

I can provide some initial text, if there is an agreement to replace the security section. 


Editorials (mainly suggestions to improve readability):
- General: There are many places where the dots are misplaced, e.g., in
 - Section 1, 2nd paragraph, " paradigm [Survey].The". This should read "paradigm [Survey]. The" (space between dot and The)
- Which Internet draft template is being used for this draft? The new templates have the "Abstract"  before the part on " Status of this Memo" and " Copyright Notice". 
- Section 1, 2nd paragraph, comma missing, replace "like CNN [CNN] PPstream" with "like CNN [CNN], PPstream"
- Section 1, 2nd paragraph, replace "Client-Server" with "client-server". The spelling of this is not consistent in the draft.
- Section 1, 4th paragraph, replace "Almost all these systems" with " Almost all of these systems".
- Section 1, 4th paragraph, replace "P2P streaming, the open protocols will dynamically reduce  " with "P2P streaming, open protocols may reduce "
- Section 2, paragraph starting with "PPSP", replace "The abbreviation of P2P streaming protocols" with "The abbreviation of Peer-to-Peer Streaming Protocols"
- Section 2, paragraph starting with "Tracker", replace "list of peers storing chunks for a specific channel or streaming file" with "list of peers which participate in a specific video channel or in the distribution of a streaming file". 
- Section 2, paragraph starting with "Tracker", replace "from peers for peer lists" with "from peers with a list of candidate peers".
- Section 3, 1st paragraph, replace "The problems brought by proprietary" with "The problems imposed by proprietary"
- Section 3.1, title of this section, replace "Difficulties for ISP in deploying P2P caches" with "Difficulties for ISPs in deploying P2P caches"
- Section 3.1, 1st paragraph, replace "P2P  cache is used to reduce the" with "P2P caches are used to reduce the" or "P2P   caching is used to reduce the"
- Section 3.1, 2nd paragraph, replace "With PPSP, P2P cache can detect" with "With PPSP, a P2P cache can detect"
- Section 3.1, 2nd paragraph, the last sentence, there are two commas between "tracker/peer protocol" and "which is easier..."
- Section 3.2, 2nd paragraph, replace "Similar to the cache case, this" with "Similar to the caching case in Section 3.1, this"
- Section 3.3, 1st paragraph, last sentence, the dot at the end is missing. 
- Section 3.3, 2nd paragraph, page 10, replace "trackers and peers need more information" with "trackers and peers may need more information"
- Section 3.3, 2nd paragraph, page 10, there is terminology collision, as serving gateway is translated to GGSN. A change of a SGSN will not be noticed by the terminal. Moving to a new GGSN might be. However, moving to a new GGSN might be experience like any other event where the IP address changes. 
- Section 3.4, 1st paragraph, replace "In other word" with "In other words"
- Section 3.4, 1st paragraph, replace "multiple programs in one resource constraint" with "multiple programs in a resource constraint"
- Section 4, 1st paragraph: replace full 1st paragraph with
"The objective of the PPSP working group is to design a unified peer- to-peer streaming protocol (PPSP) to address the problems discussed in the preceding sections."
- Section 4, 3rd paragraph: replace "and then retrieve for wanted streaming" with "and then retrieve the wanted streaming"
- Section 4, 4th paragraph: replace " topology e.g., a tree." With " topology, e.g., a tree."
- Section 4, 4th paragraph: replace "(maybe with recommended order)" with "(potentially in a recommended order)"
- Section 4, 4th paragraph: replace "Few practical systems" with "Few commercially deployed"
- Section 4, 5th paragraph: what is "unfounded data"?
- Section 4, 6th paragraph: move this paragraph to page 12 before paragraph starting with "In detail,"
- Section 4, last paragraph, page 12: I'm not sure that we still need this paragraph. Can we remove it?
- Section 5, 1st paragraph, there is a leftover: " <Text for this section>".
- Section 5.2, 1st paragraph, replace "Also it can also talk" with "It can also communicate"
- Section 5.3, 2nd paragraph, replace " With PPSP Peers can identify the types of access networks, their load/congestion information" with " With PPSP, peers may be able to identify the type of access networks, average load". Do not include congestion information, as this information is anyhow too volatile to be tracked by some entity of the peer network, other than the peers which are anyhow directly communicating with each other.
- Section 5.3, 2nd paragraph, replace "be selected, which will lead to" with "be selected, which may lead to"
- Section 5.5, 1st paragraph, replace "section3" with "Section 3"
- Section 5.5, 1st paragraph, replace "nodes in the network" with "nodes at the network"
- Reference section: This section does not follow the style of references as used in the RFC series and needs to be updated.

Kind regards

  Martin

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