The Notre Dame Marching Band is the oldest college marching band in the country. They have been around for 173 years - long before Notre Dame football began.
The Band of the Fighting Irish is huge with over 400 members, virtually all with instruments. They have no color guard, twirlers, or dance team in the band. I think the only auxiliary unit is the 8 member Irish Guard. Members of the Irish Guard used to have to be at least 6'2" but I think that may no longer be a requirement.