Pretty interesting discussion. Almost members from all the countries mentioned to be involved are present. I just wanted to add few facts that may have been mentioned previously aswell.
It must first be understood we are talking in context of 2012 so the forces will not only have what they have today but also much better equipment. Apperently both Chinese & Pakistanis have mentioned some of what they are going to buy/induct, produce, upgrade etc by 2010-15.
Coming to the scenerio. Now history tells us "alliances always win". E.g: WaterLoo where Nepolian was defeated by European Alliance, WW2 Germans, Japs & faciast Italy lost to much bigger European-American alliance. Considering this China being the main player in the conflict has larger alliance in the region & the main front line allies against India would be Pakistan, Bengladesh (never forget them, India helped creat Bangladesh just to add an other countries name in its enemies list), Mayanmar(Burma). India in the region has friends in Nepal & Srilanka but they cant do any thing for India even in one-to-one wars besides they are slipping their friendship away from India. Srilanka has started to make better relations with China. So the only country left is Russia. But Russia is a big Question mark. I doubt they will venture into this war specialy when China is leading it. Now there is U.S aswell but the best they would do would be bar Pakistan's arms export instead of joining India. Pakistan is no enemy of U.S. so U.S wont go to war with it & they wont be willing to face China specialy in a war where they have nothing to gain.
Now in the similar political-diplomatic scenerio Pakistan also happens to have its alliance in Middle East namely: Saudi Arabia & UAE which are willing to help countries. They even land their fighter jets to Pakistan. (Saudi F-5s flew to Pakistan in 1971 & PAF trains on UAE F-16s & Mirage2000-9 of UAE & PAF has flew these fighters to Pakistan many times from their home bases). Recently India pissed the Iranians off by voting against them in IAEA & Iran also looking for greater relations with China would not be of any support to India. What remains is Afghanistan & they wont do $H!T to Pakistan, they dnt even have their own army nor a sea (since we are talking mostly on naval bases).
Lets counts "Israel" now aswell shall we. There is no doubt Israel has better relations with China than India & Pakistan recently has abolished the "heat" even though it does not accept Israel as nation. This is importent for Israel to get warm with Pakistan & they recently accepted it them selves. In addition to make relations better they re phrased their former statment of "Kashir belongs to India" to "Both countries should solve it by dialogue". So I guess the only hope for India in the West Asia/Middle East is of no use. India could have looked upon Egypt which once had bad relations with Pakistan but look at them now. Producing K-8 & planning to buy JF-17 Thunder (Both Pakistan-China joint ventures) so no chance there.
So politicaly, diplomaticaly & geographicaly India is surrounded by enemies (it made it self) & it does not have alliance any where in the region & no one to help them in "Bay Of Bengal" & "Arabian Sea".
Now lets come back to Geography in military point of view:
In the West-Arabain Sea Allaince
China if ventures in Arabian sea against India it does not necessarily has to go back to Chinese sea for refueling, maintainance, repair etc (what ever post battle needs). There is Pakistan's Gwadar port, Pasni & Karachi welcoming them with open arms.
GWADAR:
It is not only a gateway to economic advancement of Pakistan but also a "major Naval Base" in the region. Although Agusta-B would be produced near Karachi, the new Subs PN is looking to buy would be produced at Gwadar. The Chinese F-22P will also be build there & PLAAN may build its own naval docks there suiting their ships. U.S & India have already shown their concern over heavy Chinese presence in the Arabian sea but U.S feels that if it stays away there would be no trouble besides U.S has its own interest of draining oil through Gwadar(This again leaves India alone).
In the West Iran would also not mind allowing PLAAN to dock at its ports but China already plans on making advance naval port at Gwadar along with Pakistan & now recently Saudi Arabi, UAE, Singapore, Malaysia & some other East Asian countries have asked approval to dock their naval ships at Gwadar for the "MARCHENT NAVY" program.
In the East- Bay of Bengal Alliance;
China plans on developing a port at Chittagong in Bangladesh. Its primary objective is economic development of BD but it now doubt serve as secondry stand by naval port to China.
Now between Gwadar, Pasni & Karachi (in Pakistan) & Dacca & Chittagong (in BD) is India. With Chinese navy present at both sides of India, PN will be facing hell lot of a trouble. It can not divert all its forces to West to Pakistan where PN & PLAN await them nor can they divert all its naval forces to East where China, BD, possibly North Korea & some other Chinese alliances r awaiting them. When it decides to split, China & alliance will get no better chance to move in from both sides aswell as move from down under to surround IN & blocking Indian seas at that time.
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In 1965 & again in 1971 PN learned the in capability of IN to locate enemy subs. For hours Ghazi submarine had been venturing near Indian AirCraft carieer Veerant or Vekrant or what ever, Indian intelegence also had a word that Ghazi was in Indian waters yet the failed to locate. Ghazin on the other hand was not to attack IN but instead to lay down sea mines & its own sea mines put end to it (which india couldnt do). It accidentlu hit its own mines.
2 other Subs had later sunk IN ships, opeing the way for PN surface ships to attack IN main base at "Somnath Mandir" which dissabled IN attacks near Karachi.
PN is now building Agusta-90B (not buying) & plans to build 2 Agusta-90Bs per 8 to 10 months & in addition add another advance Submarine to its list. PN plans to build force on advance subs. In addition PLAN has pretty good Subs to counter IN either alone or with PN.
PLAN & PN plan to produce more than required F-22P frigates. The extra ones to perform job of "Marchant Navy" & escort trade ships but in war time they can perform battle missions. In addition PN has been offered frigates by both U.S & Britain.
In the military aviation (in context of 2012) PAF will have abt 119 F-16s all at the level of Block 50/52+. Pakistan has already been given clearance by Sweden earlier this month for the purchase of SAAB-ERICSON Erieyes while it is speculated PN might purchase separate system (E2C HawkEye).
8 more P3C orions are planned taking the inventory to 12.
Joining the forces would be JF-17/FC-1 which after seeing recent upgrades & details provided by PAC-CAC seems to be an advance 3rd gen fighter rather than low level 3rd gen fighter. It is now actualy suppose to threat IAF MiG-29.
Recently PAF's vice airmarshal said that advance 4th generation fighters available from European & the owner countries are willing to sell us. We will make decision after the practical evaluation. Only two names have been sorted : Sweden's JAS-39 Gripen & French "Rafale". Its most probably seems Gripen. So there would be strong air support to PN aswell as PLAN. We should not forget PLAAF's JH-7, J-10, Su-30MKK-MKK2, J-11 & J-8.
Rightn ow PAF has Mirage-5 ROSE III upgraded by SEGAM which can also fire MICA (no details accept a pic on one of PAF Mirage-5ROSEIII was revealed - carrying MICA was made available -pic was available at defencetalk.com) But by 2012 PAF plans to sell its old machinery capable of firing advance weapons (E.g: F-7P, F-7PG, Mirage-3ROSE III & Mirage-5ROSEIII) to Bangladesh & I believe BD, North Korea & Mayanmar will also be getting PLAAF's expelled F-7s. This will bring surplus air defence to BD & Mayanmar enough to make India split its airforce fighters around all the allied nations, again giving the alliance an advantage.
Since Gwadar is very importent port of China aswell there is a word that China might also establish a joint airbase at Gwadar with Pakistan thus bring many of PLAAF & PLAN fighters (except F-16s due to U.S pressure) togather.
Consider IAF facing PAF-PLAAF (Su-30MKK-MKK2 escorted by PAF's 4th gen fighters or F-16s from Karachi joining on the way instead of taking off with sukhois from joint airbase. Besides that there would be mass escort & support by FC-1s/JF-17s).
Bangladesh plans to buy 50 to 60 JF-17s & PAC has already laid their fighter plans on the paper. So in the East there are also JF-17s, Mirage-3/5ROSEIII, F-7P, F-7PG to face IAF's Mig-29Ms & MiG-29s of IAF.
Lets consdier land escilation. PA has already rolled out its Al-Khalid (unlike IA's Arjun). Al-Khalid is a threat to IA's T-90. Although its base tanks (Chinese T-90 was inferior to it) but the upgrades through european avionics made it world class & now it is on export market. Saudis & UAE are willing to buy it while Pakistan seeks avionics purchase fron General Dynamics (builders of M-1 Abrahms). In addition PA has T-50s upgrage, T-60 (Al-Zarar upgrade), T-80, T-84 & T-84 & Pakistan plans to have 5000 Tanks. Its alot but thats what the word is out there. 1000 Tanks for each province. Al-Khalids are great desert & hot climatic region tanks & IA does not have any tank that can perform very well in hot climate & desert regions at this moment & Arjun seems to be a long shot.
China on the other hand tanks good enough to break IA's tanks on the northern borders & India knws PLAAF's capability from 1962's war.
Now the only hope I see for India is Russia. But would Russia risk relations with China? & if it does how would it provide support. China blocks the way & there is no USSR near Pakistan's Western Borders.
These war scenerios have been analysed before. U.S has done it probably more than India might have done it. All these patriot sells & heavy marketing of F-18 fighter is the counter action of U.S. By this U.S is keeping it self away from the war on the other hand it also feeds Pakistan with its weapons. U.S weapons to india are to counter china not Pakistan. F-18s will provide good defence against any joint air attack but china, pakistan n allies but it wont be able to provide good offense as it would be facing larger force drived by quantity+quality. IAF is gaining quality but soon would be loosing quantity once MiG-27, MiG-21, Jaguars & Harriers start to retire, leaving Indian military aviation with Mirage-2000Hs, MiG-29s, MiG-29M, Su-30MKI.
(Like to add that Pakistan also plans to buy 12 Qatari Mirage2000-5s & hand them over to PAF's naval aviation sqdn in Karachi - recently it was reported India was backing out---earlier it was said Pakistan was backing out-its pretty confusing).
USA also signed a deal with Pakistan in 2002 that it will give away 2nd hand equipment (including Fighter Jets) for free if/when Pakistan need/require them. Pakistan would only have to pay for their upgrades. This gives PA, PAF & PN to induct pretty good quantity & quality of war machinese by 2012.
Hence if in 2012 or 2015 an allied attack is declared on India..India would be facing huge trouble. India is not sleeping, now doubt it is going to make purchase of good war machinese before 2015 & in 2012 they would have good machinese but the quantity & quality Pakistan+China+Alliance will have would be too much for them to handle.
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On the other hand, this is all nothing but fantasy. Both Pakistan & China say they no longer believe in armed actions but instead diplomatic actions & both seem to be showing great success in it. If there is to be any thing it would be nothing more than a COLD WAR in which armies would be staring into each others eyes, making faces, faking like they are abt to strike but they end of the day every one would go back to bed.