I used to run on country roads and got chased a fair amount. My strategy was to to turn around, face the dogs and yell at them as loud as I could. Fortunately this usually worked. However I knew a guy who was attacked by pit bulls in his own yard, had an hour standoff and had his arm broken. You really can’t stop a determined dog without a weapon (former TX governor Rick Perry once shot a coyote while out on a jog). The exception to this that I now remember is a 7 foot tall pretty built basketball coach from my HS who was out for a jog when an aggressive dog jumped up on him. He punched it in the face and it died. Pretty sad and also not something any runner I know could likely pull off.