Armour in the Realms is essentially the same as described in the PHB. Of course Armour Class now scales upward, not downward, and movement rates are now affected by the weight and bulk of the armour.
Consult the table to see the new armour class and movement rate.

Masterwork Armour:

Just as with weapons, you can purchase or craft masterwork versions of armour and shields. Such a well made armour functions like the normal version, except that it is lighter and thus less encumbering, weighing only two thirds of the original weight. Wearing such well made armour also makes it easier to move, so when consulting the table below for armour movement rates, consider the rate to be one category better. Thief ability penalties are reduced by 5%. Arcane spellcasters who invest in Armour proficiency benefit from masterwork armour (see weapon proficiency section). Armour of this quality adds 150gp to the value.

Shields:

Shields are slightly different from the descriptions in the Player’s Handbook. Bucklers and small shields confer a bonus to AC of +1. Medium shields confer a +2 bonus, large shields confer a +3 bonus, and body shields confer a +4 bonus.
When using a shield in a shield bash, they do damage as follows: Bucklers 1d3 (speed 3), Small 1d4 (speed 4), Medium 1d6 (speed 6), Large 1d8 (speed 8), Body 1d10 (speed 10). Treat all as Bludgeoning weapons. Using a shield bash means you forego the AC bonus it confers for that round, unless you have the Shield Bash fighting style option.

Masterwork Shields:

Masterwork shields are exceptional creations. They are lighter, and more durable than their regular counterparts. Masterwork shields weigh 2/3 of the listed weight, rounded down. They cannot be sundered, and receive a +1 to all item saving throws. Shields of this quality add 100 gp to the value.