Syria Talks: What You Need to Know

— -- The United States, Russia, Saudi Arabia and even Iran have gathered with several other countries in Vienna, Austria, in pursuit of a way to end the four-year Syrian conflict. Whether there is a breakthrough remains to be seen, but this is what you should know:

What's at Stake?

The main issue on the negotiating table is the fate of Syrian President Bashar al-Assad, and the political transition in Syria, seen as a potent contributor to enabling the defeat of ISIS.

Thorny components are being negotiated: What happens to the embattled Assad; what role, if any, does he play in a political transition; and how long the transition will be.

A plenary meeting discussing the matter has now entered its sixth hour.

A source attending the plenary meeting confirmed there was a serious discussion about a political transition of four to six months.

A senior Mideast official familiar with the Iranian position told Reuters that "Iran is ready to make a compromise by accepting Assad remain for six months."

Iran's deputy foreign minister was quoted by Iranian journalists saying he "strongly rejects" claims that Tehran has agreed to back a proposal that requires the Syrian president to step down in six months.

Iran has committed resources and men to bolstering Assad. It has lost a number of high-ranking military personnel in battles in Syria in the past weeks alone. It has maintained that it is up to the Syrian people to decide who leads them.

Even among countries that are opposed to the Syrian president, the time frame of the transition that they are prepared to accept is not unanimous.

Saudi Arabia, which backs various rebel factions with funding and U.S.-made weapons, has adopted the most intransigent position. "They have been the most forceful in pushing for a defined time frame; they don't want to leave Assad room to scuttle any potential agreement,” according to Fahad Nazer, a former political analyst at the Saudi embassy in D.C., and a senior political analyst with JTG Inc.

The Saudi foreign minister told the BBC Thursday that Assad’s leaving is certain, either through a political process or through force.

Who Is There?

This is the first international meeting about the Syria crisis to which Iran was invited.

The United States, Russia, Saudi Arabia, Turkey and Iran, in addition to France, the U.K., Germany, Jordan, Iraq, Egypt, Qatar, the United Arab Emirates, Lebanon and China -- as well as the European Union and United Nations -- are present in a mix of countries involved in the fighting and suffering from the outflow of refugees.

Oman, a country that maintains good relations with the United States and with Syria, and which played an important mediation role in the negotiations on Iran's nuclear program, is also participating.

Neither the Syrian government nor the opposition and armed factions were invited. A Western and a non-Western diplomatic source in Vienna confirmed that a second round of negotiations, including the Syrian parties, is being considered, though the details about which of the armed groups that make up what is known as the Free Syrian Army would be present remain under advisement.

Russia's deputy foreign minister Mikhael Bogdanov said today "we support their participation as a structure; we do not yet understand who will represent it."

Why We Should Care

ISIS and the refugees.

The hope among observers is that the fight against ISIS will be bolstered by a political transition that leads to a ceasefire between the Syrian government and rebels and a concentration of military assets against ISIS.

The most sustainable solution to the outpouring of Syrian refugees to neighboring countries and to Europe is believed to be a political solution that would allow them to go home, a preference most refugees express along the route in Europe.