The "western" media is reporting the crisis in Libya as something similar to what happened in Egypt and Tunisia. But this is not a modern youth movement protesting against a dictatorship, this is a developing civil war between tribal entities – not exactly a novelty in Libya.

A bigger version of the map can be found at the Public Intelligence Blog
From a 2002 piece on Tribal Rivalries in Libya which explains why some army units are now with the rebels:
Such rivalries are most pronounced in the armed forces. Each of the main tribes is represented in the military establishment and the various popular and revolutionary committees. For instance, Qadhafi's Qadhadfa tribe has an ongoing rivalry with the Magariha tribe of Abdel Sallam Jalloud, the man who was second-in-command in the country for decades until he fell out of favour.
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The Warfalla tribe, which turned against Qadhafi during the coup attempt in 1993, is numerous and is closest to Jalloud's Magariha tribe. The Al Zintan tribe backed the Warfalla as well. The coup attempt was spearheaded by Warfalla officers in the Bani Walid region, 120 km south-east of Tripoli. The main reason for the coup attempt was that, despite its size, this tribe was poorly represented in the regime and only occupied second-echelon posts in the officers' corps.
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Moreover, Warfalla tribal officers have been excluded from the air force. The air force is reserved almost exclusively to the Qadhadfa tribe, to which Qadhafi belongs. It was the air force which crushed the coup attempt in October 1993.
It is possible that it, again, will be the air force that will put down this insurrection. But that end may also depend on one major tribe which so far has not taken a definite position:
The leadership of the Magariha tribe acknowledges a debt of gratitude to Gaddafi and his regime for securing the return of one of the tribe's members, Abdel Baset al-Megrahi, from prison in Britain after he was convicted of being behind the Lockerbie bombing. However sources also told Asharq Al-Awsat that this has not prevented a number of youths of the Magariha tribe from participating – with members from other tribes – in the demonstrations and protests against Gaddafi's rule, especially in cities in eastern and southern Libya.
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Experts say that the Magariha tribe is in the best position to carry out a coup against the Libyan leader, as many members of this tribe are in sensitive and senior positions of the Libyan government and security services.
There is more on the allegiances of the major 30 tribes and clans in Libya in the above piece. Additional information is here.
The misrepresentation of this conflict in the media may well lead to military intervention by "western" forces. These would then have to fight those tribes which for whatever reason support Ghadaffi. With "western" intervention the situation on the ground would quickly deteriorate. This would cost a lot more lives than any situation in which the Libyan people fight this out by and for themselves.